Mega Sudoku Printable Puzzle | Puzzler® - Free Printable

Let’s solve this Mega Sudoku puzzle step by step.

This is a 16x16 Sudoku, which means:
- The grid has 16 rows and 16 columns.
- It’s divided into 4x4 blocks (so there are 16 blocks total).
- Each row, each column, and each 4x4 block must contain all numbers from 1 to 16 — no repeats.

We’ll start by looking for cells that have only one possible number based on what’s already in their row, column, or block.

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Step 1: Look at Row 1 (top row)

Row 1 currently has:
_ 3 15 _ 11 7 _ _ 9 14 _ _ 16 6 _ _

Missing numbers in Row 1: 1,2,4,5,8,10,12,13

Now check Column 1 (first column) — it has:
_, 13, 14, _, _, 3, 7, _, 13, 15, 4, _, _, 16, 9, _

Wait — we see “13” appears twice in Column 1? That can’t be right. Let me double-check the image.

Actually, looking again — Row 1, Col 1 is empty. Row 2, Col 1 is 13. Row 3, Col 1 is 14. Row 4, Col 1 is empty. Row 5, Col 1 is empty. Row 6, Col 1 is 3. Row 7, Col 1 is 7. Row 8, Col 1 is empty. Row 9, Col 1 is 13 — oh! Wait, that’s a problem — two 13s in Column 1? But that can’t happen in Sudoku.

Hold on — let me re-express the grid properly.

Actually, I think I misread. Let me write out the full grid as given:

Row 1: [ ] 3 15 [ ] 11 7 [ ] [ ] 9 14 [ ] [ ] 16 6 [ ] [ ]

Row 2: 13 [ ] [ ] [ ] [ ] 4 11 [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] 3

Row 3: 14 [ ] 8 7 2 1 [ ] 15 5 [ ] 10 6 4 13 [ ] 12

Row 4: [ ] [ ] 10 [ ] [ ] 8 [ ] [ ] [ ] [ ] 3 [ ] [ ] 9 [ ] [ ]

Row 5: [ ] [ ] 2 [ ] [ ] 9 [ ] [ ] [ ] [ ] 13 [ ] [ ] 5 [ ] [ ]

Row 6: 3 [ ] 11 4 14 13 [ ] 7 8 [ ] 16 5 12 15 [ ] 1

Row 7: 7 [ ] [ ] [ ] [ ] [ ] 2 6 [ ] [ ] [ ] [ ] [ ] [ ] 10 [ ]

Row 8: [ ] 14 9 [ ] [ ] 15 1 [ ] [ ] 4 11 [ ] [ ] 8 13 [ ]

Row 9: [ ] 13 6 [ ] [ ] 16 11 [ ] [ ] 14 8 [ ] [ ] 4 2 [ ]

Row 10: 15 [ ] [ ] [ ] [ ] [ ] 12 10 [ ] [ ] [ ] [ ] [ ] [ ] [ ] 8

Row 11: 4 [ ] 3 5 1 14 [ ] 9 13 [ ] 6 16 15 12 [ ] 7

Row 12: [ ] [ ] 16 [ ] [ ] 3 [ ] [ ] [ ] [ ] 4 [ ] [ ] 6 [ ] [ ]

Row 13: [ ] [ ] 4 [ ] [ ] 12 [ ] [ ] [ ] [ ] 1 [ ] [ ] 3 [ ] [ ]

Row 14: 16 [ ] 12 11 3 6 [ ] 10 15 [ ] 2 4 1 7 [ ] 13

Row 15: 9 [ ] [ ] [ ] [ ] [ ] 16 14 [ ] [ ] [ ] [ ] [ ] [ ] 11 [ ]

Row 16: [ ] 15 13 [ ] [ ] 4 14 [ ] [ ] 3 7 [ ] [ ] 2 12 [ ]

Okay, now let’s look for easy placements.

Look at Row 3:
14 _ 8 7 2 1 _ 15 5 _ 10 6 4 13 _ 12

Missing numbers: 3,9,11,16

Check Column 2: has 3 (row1), then blank, blank, blank, blank, blank, blank, 14, 13, blank, blank, blank, blank, blank, blank, 15 → so 3 is already in col2 → so row3,col2 cannot be 3.

Column 7: row3,col7 is blank. What’s in col7? Row1: blank, row2: blank, row3: blank, row4: blank, row5: blank, row6: blank, row7: 2, row8: 1, row9: 11, row10: 12, row11: blank, row12: blank, row13: blank, row14: blank, row15: 16, row16: 14 → so 2,1,11,12,16,14 are taken → missing 3,4,5,6,7,8,9,10,13,15 → too many options.

Maybe try blocks.

Top-left 4x4 block (rows 1-4, cols 1-4):

Cells:
R1C1: ?, R1C2:3, R1C3:15, R1C4:?
R2C1:13, R2C2:?, R2C3:?, R2C4:?
R3C1:14, R3C2:?, R3C3:8, R3C4:7
R4C1:?, R4C2:?, R4C3:10, R4C4:?

Numbers present: 3,15,13,14,8,7,10 → missing: 1,2,4,5,6,9,11,12,16

Too many missing.

Let’s try a different approach — look for numbers that appear often and see where they can go.

For example, look at number 1.

Where is 1 already placed?

Row 3, Col 6 → 1
Row 8, Col 7 → 1
Row 9, Col 7 → 11? No, row9,col7 is 11. Row8,col7 is 1.
Row 11, Col 5 → 1
Row 14, Col 13 → 1
Row 16, Col 15 → 12? No.

List of 1s:

- R3C6 = 1
- R8C7 = 1
- R11C5 = 1
- R14C13 = 1

Also, R9C7 is 11, not 1.

Now, let’s find where else 1 can go.

Consider Row 1: missing 1,2,4,5,8,10,12,13

Can 1 go in R1C1? Check column 1: has 13,14,3,7,13 (wait, R9C1 is 13? And R2C1 is 13 — that’s duplicate! Oh no — that can’t be.

Wait — I think I made a mistake earlier. Let me check the original image description again.

Looking back at the user's input:

In Row 2: "13" in first cell
In Row 9: "13" in second cell? No — Row 9 starts with "_ 13 6 ..." so R9C2 = 13, not R9C1.

Ah! I misread. Let me correct:

Row 1: C1=?, C2=3, C3=15, C4=?, C5=11, C6=7, C7=?, C8=?, C9=9, C10=14, C11=?, C12=?, C13=16, C14=6, C15=?, C16=?

Row 2: C1=13, C2=?, C3=?, C4=?, C5=?, C6=4, C7=11, C8=?, C9=?, C10=?, C11=?, C12=?, C13=?, C14=?, C15=?, C16=3

Row 3: C1=14, C2=?, C3=8, C4=7, C5=2, C6=1, C7=?, C8=15, C9=5, C10=?, C11=10, C12=6, C13=4, C14=13, C15=?, C16=12

Row 4: C1=?, C2=?, C3=10, C4=?, C5=?, C6=8, C7=?, C8=?, C9=?, C10=?, C11=3, C12=?, C13=?, C14=9, C15=?, C16=?

Row 5: C1=?, C2=?, C3=2, C4=?, C5=?, C6=9, C7=?, C8=?, C9=?, C10=?, C11=13, C12=?, C13=?, C14=5, C15=?, C16=?

Row 6: C1=3, C2=?, C3=11, C4=4, C5=14, C6=13, C7=?, C8=7, C9=8, C10=?, C11=16, C12=5, C13=12, C14=15, C15=?, C16=1

Row 7: C1=7, C2=?, C3=?, C4=?, C5=?, C6=?, C7=2, C8=6, C9=?, C10=?, C11=?, C12=?, C13=?, C14=?, C15=10, C16=?

Row 8: C1=?, C2=14, C3=9, C4=?, C5=?, C6=15, C7=1, C8=?, C9=?, C10=4, C11=11, C12=?, C13=?, C14=8, C15=13, C16=?

Row 9: C1=?, C2=13, C3=6, C4=?, C5=?, C6=16, C7=11, C8=?, C9=?, C10=14, C11=8, C12=?, C13=?, C14=4, C15=2, C16=?

Row 10: C1=15, C2=?, C3=?, C4=?, C5=?, C6=?, C7=12, C8=10, C9=?, C10=?, C11=?, C12=?, C13=?, C14=?, C15=?, C16=8

Row 11: C1=4, C2=?, C3=3, C4=5, C5=1, C6=14, C7=?, C8=9, C9=13, C10=?, C11=6, C12=16, C13=15, C14=12, C15=?, C16=7

Row 12: C1=?, C2=?, C3=16, C4=?, C5=?, C6=3, C7=?, C8=?, C9=?, C10=?, C11=4, C12=?, C13=?, C14=6, C15=?, C16=?

Row 13: C1=?, C2=?, C3=4, C4=?, C5=?, C6=12, C7=?, C8=?, C9=?, C10=?, C11=1, C12=?, C13=?, C14=3, C15=?, C16=?

Row 14: C1=16, C2=?, C3=12, C4=11, C5=3, C6=6, C7=?, C8=10, C9=15, C10=?, C11=2, C12=4, C13=1, C14=7, C15=?, C16=13

Row 15: C1=9, C2=?, C3=?, C4=?, C5=?, C6=?, C7=16, C8=14, C9=?, C10=?, C11=?, C12=?, C13=?, C14=?, C15=11, C16=?

Row 16: C1=?, C2=15, C3=13, C4=?, C5=?, C6=4, C7=14, C8=?, C9=?, C10=3, C11=7, C12=?, C13=?, C14=2, C15=12, C16=?

Okay, now let's verify duplicates.

Column 1: R2=13, R3=14, R6=3, R7=7, R10=15, R11=4, R14=16, R15=9 — all unique so far. Good.

Column 2: R1=3, R8=14, R9=13, R16=15 — others blank. OK.

Now, let's try to fill in some obvious ones.

Look at Row 6:
3 _ 11 4 14 13 _ 7 8 _ 16 5 12 15 _ 1

Missing numbers: 2,6,9,10

Positions: C2, C7, C10, C15

Check C2: what's in column 2? R1=3, R8=14, R9=13, R16=15 — so 3,13,14,15 taken. Missing 1,2,4,5,6,7,8,9,10,11,12,16 — but for row6, we need 2,6,9,10 — all possible in C2? Yes.

C7: column 7 has R7=2, R8=1, R9=11, R10=12, R15=16, R16=14 — so 1,2,11,12,14,16 taken. For row6, missing 2,6,9,10 — 2 is already in col7 (R7C7=2), so C7 cannot be 2. So possible: 6,9,10

C10: column 10 has R1=14, R3=?, R4=?, R5=?, R6=?, R7=?, R8=4, R9=14 — wait R1C10=14, R9C10=14 — duplicate! Oh no!

R1C10=14, R9C10=14 — same column? Column 10.

R1C10=14, R9C10=14 — that's two 14s in column 10. That's invalid.

But in the original problem, is that correct?

Let me check the user's input:

Row 1: ... 9 14 ... → C9=9, C10=14

Row 9: ... 14 8 ... → C10=14, C11=8

Yes, both have 14 in column 10. That's a conflict.

Unless... perhaps I miscounted the columns.

Let's list Row 1 carefully:

The string is: "3 15 | 11 7 | 9 14 | 16 6" — but that's grouped. Actually, the grid is 16 columns, and the vertical lines are just separators for 4x4 blocks.

So Row 1: positions 1 to 16:

From left:
Col1: (empty)
Col2: 3
Col3: 15
Col4: (empty)
Col5: 11
Col6: 7
Col7: (empty)
Col8: (empty)
Col9: 9
Col10: 14
Col11: (empty)
Col12: (empty)
Col13: 16
Col14: 6
Col15: (empty)
Col16: (empty)

Row 9: "_ 13 6 _ _ 16 11 _ _ 14 8 _ _ 4 2 _"

So:
Col1: _
Col2: 13
Col3: 6
Col4: _
Col5: _
Col6: 16
Col7: 11
Col8: _
Col9: _
Col10: 14
Col11: 8
Col12: _
Col13: _
Col14: 4
Col15: 2
Col16: _

So yes, R1C10=14 and R9C10=14 — same column, same number — impossible in Sudoku.

This suggests there might be a typo in the problem or in my reading.

Perhaps the "14" in Row 9 is in a different column.

Let's count the entries in Row 9: "_ 13 6 _ _ 16 11 _ _ 14 8 _ _ 4 2 _"

That's 16 items: 1:_ ,2:13,3:6,4:_,5:_,6:16,7:11,8:_,9:_,10:14,11:8,12:_,13:_,14:4,15:2,16:_

Yes, C10=14.

And Row 1: "3 15 | 11 7 | 9 14 | 16 6" — but this is grouped; actually, the full row is: _ 3 15 _ 11 7 _ _ 9 14 _ _ 16 6 _ _

So C1:_, C2:3, C3:15, C4:_, C5:11, C6:7, C7:_, C8:_, C9:9, C10:14, C11:_, C12:_, C13:16, C14:6, C15:_, C16:_

So C10=14 for both R1 and R9 — conflict.

Unless the puzzle has a mistake, or I need to assume it's correct and proceed.

Perhaps in Mega Sudoku, the rules are different? No, standard Sudoku rules apply.

Another possibility: maybe the "14" in Row 9 is not in C10. Let's see the grouping.

In the image, there are vertical lines after every 4 columns, so the groups are cols 1-4, 5-8, 9-12, 13-16.

In Row 9: "_ 13 6 _ | _ 16 11 _ | _ 14 8 _ | _ 4 2 _"

So:
Block 1 (cols 1-4): _,13,6,_
Block 2 (cols 5-8): _,16,11,_
Block 3 (cols 9-12): _,14,8,_
Block 4 (cols 13-16): _,4,2,_

So C9=_, C10=14, C11=8, C12=_

Similarly, Row 1: "_ 3 15 _ | 11 7 _ _ | 9 14 _ _ | 16 6 _ _"

So C9=9, C10=14, C11=_, C12=_

So yes, both have 14 in C10.

This is a problem. Perhaps it's a typo, and in Row 9, it's not 14 in C10.

Maybe it's 1 in C10 or something else.

To resolve this, I recall that in some puzzles, the given numbers are correct, and we have to work around it, but here it's clearly a duplicate.

Perhaps I should contact the user, but since I can't, I'll assume that in Row 9, C10 is not 14, but let's see the context.

Another idea: perhaps the "14" in Row 9 is in C9, not C10.

Let's read the string: "_ 13 6 _ _ 16 11 _ _ 14 8 _ _ 4 2 _"

If we group as per blocks:

After first 4: "_ 13 6 _" — that's cols 1-4

Next 4: "_ 16 11 _" — cols 5-8

Next 4: "_ 14 8 _" — cols 9-12

Last 4: "_ 4 2 _" — cols 13-16

So in cols 9-12: C9=_, C10=14, C11=8, C12=_

Same as before.

Perhaps in Row 1, C10 is not 14. Row 1: "_ 3 15 _ 11 7 _ _ 9 14 _ _ 16 6 _ _"

Grouped: cols 1-4: _,3,15,_
cols 5-8: 11,7,_,_
cols 9-12: 9,14,_,_
cols 13-16: 16,6,_,_

So C9=9, C10=14, etc.

I think there might be an error in the puzzle provided, but for the sake of solving, I'll assume that the puzzle is correct and perhaps I need to ignore the duplicate or something.

Maybe "Mega Sudoku" has different rules, but typically it's the same as regular Sudoku but larger.

Upon second thought, in some variants, the diagonal or other constraints, but usually not.

Perhaps the number in R9C10 is not 14, but let's look at the original text: " _ 13 6 _ _ 16 11 _ _ 14 8 _ _ 4 2 _ " — it's written as "14", so likely 14.

To move forward, I'll assume that the puzzle is solvable, and perhaps the duplicate is a red herring or I misread.

Let's try to solve it as is, and see if we can find a contradiction later.

Start with Row 6: 3 _ 11 4 14 13 _ 7 8 _ 16 5 12 15 _ 1

Missing: 2,6,9,10

C2: can be 2,6,9,10 (col2 has 3,13,14,15 — so ok)

C7: col7 has R7=2, R8=1, R9=11, R10=12, R15=16, R16=14 — so 1,2,11,12,14,16 taken. So for C7, cannot be 2 (already in col7), so possible 6,9,10

C10: col10 has R1=14, R8=4, R9=14 — oh, R1C10=14, R9C10=14 — definitely duplicate. This is a problem.

Unless R9C10 is not 14. Let's check the user's input again.

User said: " _ 13 6 _ _ 16 11 _ _ 14 8 _ _ 4 2 _ " for Row 9.

Perhaps the "14" is in C9, not C10. But in the sequence, after "_ _ " for C8 and C9? Let's index:

Position 1: _
2: 13
3: 6
4: _
5: _
6: 16
7: 11
8: _
9: _
10: 14
11: 8
12: _
13: _
14: 4
15: 2
16: _

So C9=_, C10=14, C11=8

Yes.

Perhaps in Row 1, C10 is not 14. Row 1: "3 15 | 11 7 | 9 14 | 16 6" — but this is the content, and the first cell is empty, so C1=_, C2=3, C3=15, C4=_, C5=11, C6=7, C7=_, C8=_, C9=9, C10=14, etc.

I think there's a mistake in the puzzle, but for the sake of completing the task, I'll assume that in Row 9, C10 is not 14, or perhaps it's 1, but that doesn't help.

Another idea: perhaps the "14" in Row 9 is for C9, and C10 is 8, but the text says "_ 14 8 _" for cols 9-12, so C9=_, C10=14, C11=8, C12=_

I give up on that; let's try a different cell.

Look at Row 14: 16 _ 12 11 3 6 _ 10 15 _ 2 4 1 7 _ 13

Missing numbers: 5,8,9,14

Positions: C2, C7, C10, C15

C2: col2 has R1=3, R8=14, R9=13, R16=15 — so 3,13,14,15 taken. Missing 1,2,4,5,6,7,8,9,10,11,12,16 — so 5,8,9,14 are possible, but 14 is in col2 (R8C2=14), so C2 cannot be 14. So possible 5,8,9

C7: col7 has R7=2, R8=1, R9=11, R10=12, R15=16, R16=14 — so 1,2,11,12,14,16 taken. Missing 3,4,5,6,7,8,9,10,13,15 — so 5,8,9,14 are possible, but 14 is taken, so 5,8,9

C10: col10 has R1=14, R8=4, R9=14 — duplicate, so let's say R9C10 is not 14 for now, or assume it's a different number.

Perhaps in the puzzle, R9C10 is 1, but it's written as 14.

To make progress, I'll assume that the puzzle is correct and the duplicate is intentional or I need to solve it as is.

Let's look at Block 3 (rows 1-4, cols 9-12)

Cells:
R1C9=9, R1C10=14, R1C11=?, R1C12=?
R2C9=?, R2C10=?, R2C11=?, R2C12=?
R3C9=5, R3C10=?, R3C11=10, R3C12=6
R4C9=?, R4C10=?, R4C11=3, R4C12=?

Numbers present: 9,14,5,10,6,3 — so missing 1,2,4,7,8,11,12,13,15,16

Many missing.

Perhaps start with number 16.

Where is 16 placed?

R1C13=16
R6C11=16
R9C6=16
R11C12=16
R14C1=16
R15C7=16

Also, R3C11=10, not 16.

So 16 is in: R1C13, R6C11, R9C6, R11C12, R14C1, R15C7

Now, let's see where else 16 can go.

For example, in Row 2: missing many numbers.

Perhaps use the fact that each block must have 1-16.

Let's take Block 1 (rows 1-4, cols 1-4)

Cells:
R1C1=?, R1C2=3, R1C3=15, R1C4=?
R2C1=13, R2C2=?, R2C3=?, R2C4=?
R3C1=14, R3C2=?, R3C3=8, R3C4=7
R4C1=?, R4C2=?, R4C3=10, R4C4=?

Numbers present: 3,15,13,14,8,7,10 — so missing: 1,2,4,5,6,9,11,12,16

Now, R4C3=10, etc.

Look at R4C1: what can it be? Col1 has R2=13, R3=14, R6=3, R7=7, R10=15, R11=4, R14=16, R15=9 — so taken: 3,4,7,9,13,14,15,16 — missing 1,2,5,6,8,10,11,12

For R4C1, also in block 1, missing 1,2,4,5,6,9,11,12,16 — so intersection: 1,2,5,6,11,12 (since 4,9,16 not in col1 missing, but 4 is in col1? R11C1=4, so 4 is taken, so not available. Similarly, 9 is in R15C1=9, so taken. 16 in R14C1=16, taken. So for R4C1, possible from block missing: 1,2,5,6,11,12, and from col1 missing: 1,2,5,6,8,10,11,12 — so common: 1,2,5,6,11,12

Still many.

Perhaps look for a cell with few possibilities.

Let's consider R7C2.

Row 7: 7 _ _ _ _ _ 2 6 _ _ _ _ _ _ 10 _

So missing numbers: 1,3,4,5,8,9,11,12,13,14,15,16

Col2: has R1=3, R8=14, R9=13, R16=15 — so taken 3,13,14,15 — missing 1,2,4,5,6,7,8,9,10,11,12,16

Block for R7C2 is Block 5 (rows 5-8, cols 1-4)

Block 5:
R5C1=?, R5C2=?, R5C3=2, R5C4=?
R6C1=3, R6C2=?, R6C3=11, R6C4=4
R7C1=7, R7C2=?, R7C3=?, R7C4=?
R8C1=?, R8C2=14, R8C3=9, R8C4=?

Numbers present: 2,3,11,4,7,14,9 — so missing 1,5,6,8,10,12,13,15,16

For R7C2, from row missing: 1,3,4,5,8,9,11,12,13,14,15,16 — but 3,4,9,11,14 are in the block or col? In block, 3,4,9,11,14 are present, so cannot be those. From col, 3,13,14,15 taken.

So for R7C2, cannot be 3,4,9,11,13,14,15 (from various constraints)

From row missing, remove those: so possible 1,5,8,12,16

From block missing: 1,5,6,8,10,12,13,15,16 — so common with above: 1,5,8,12,16

From col missing: 1,2,4,5,6,7,8,9,10,11,12,16 — so still 1,5,8,12,16

So R7C2 can be 1,5,8,12,16

Not very restrictive.

Let's try R1C1.

Row 1 missing: 1,2,4,5,8,10,12,13

Col1 missing: 1,2,5,6,8,10,11,12 (since taken: 3,4,7,9,13,14,15,16)

Block 1 missing: 1,2,4,5,6,9,11,12,16

So for R1C1, intersection of row, col, block missing.

Row missing: 1,2,4,5,8,10,12,13

Col missing: 1,2,5,6,8,10,11,12

Block missing: 1,2,4,5,6,9,11,12,16

Common to all three: 1,2,5,12 (since 4 not in col missing, 8 not in block missing, 10 not in block missing, 13 not in col or block, 6 not in row missing, 11 not in row missing, 16 not in row missing)

So R1C1 can be 1,2,5,12

Still not single.

Perhaps look at R3C2.

Row 3: 14 _ 8 7 2 1 _ 15 5 _ 10 6 4 13 _ 12

Missing: 3,9,11,16

Col2: has 3,13,14,15 — so 3 is taken, so R3C2 cannot be 3.

Block 1: missing 1,2,4,5,6,9,11,12,16 — so 9,11,16 are possible, 3 is not in block missing? Block has 3 already (R1C2=3), so 3 is taken in block, so R3C2 cannot be 3 anyway.

So possible 9,11,16

Now, is there any constraint that eliminates some?

Col2 has no 9,11,16 yet, so all possible.

Not helpful.

Let's try to place number 1.

1 is in: R3C6, R8C7, R11C5, R14C13

Also, R6C16=1, R7C15=10, not 1.

R6C16=1, yes.

So 1 is in: R3C6, R6C16, R8C7, R11C5, R14C13

Now, where can 1 go in Row 1? Missing 1,2,4,5,8,10,12,13

C1: can be 1 (as above)
C4: col4 has R3=7, R6=4, R14=11, R16=4 — R6C4=4, R16C4=4? R16: "_ 15 13 _ _ 4 14 _ _ 3 7 _ _ 2 12 _" so C6=4, not C4. C4 is _.

Col4: R3C4=7, R6C4=4, R14C4=11, and others blank.

So for R1C4, col4 has 4,7,11 — so 1 is possible.

Similarly, C7, C8, C11, C12, C15, C16 are empty in row 1.

But in block 1, for R1C1, we have possible 1,2,5,12

In block 2 (rows 1-4, cols 5-8):
R1C5=11, R1C6=7, R1C7=?, R1C8=?
R2C5=?, R2C6=4, R2C7=11, R2C8=?
R3C5=2, R3C6=1, R3C7=?, R3C8=15
R4C5=?, R4C6=8, R4C7=?, R4C8=?

Numbers present: 11,7,4,11,2,1,15,8 — oh, 11 appears twice: R1C5=11, R2C7=11 — same block? Block 2 is cols 5-8, so R1C5 and R2C7 are both in block 2 — duplicate 11! Another problem.

R1C5=11, R2C7=11 — both in block 2 — impossible.

This confirms that there are errors in the puzzle as given.

Perhaps in Row 2, C7 is not 11, but the user wrote "4 11" for C6 and C7, so C6=4, C7=11.

And R1C5=11.

So duplicate 11 in block 2.

This puzzle has multiple duplicates, so it's invalid.

For the sake of providing an answer, I'll assume that the intended puzzle is correct, and perhaps the numbers are different, but since I can't change it, I'll stop here.

But the user expects a solution, so perhaps I need to output the completed grid as per standard solving, but with the given numbers, it's impossible.

Maybe "Mega Sudoku" allows repeats, but that doesn't make sense.

Another possibility: perhaps the grid is 16x16, but the numbers are from 1 to 16, and the given numbers are correct, and I need to solve it, but with the duplicates, it's not possible.

Perhaps in the image, the numbers are placed correctly, and my parsing is wrong.

Let's look at the user's input for Row 2: "13 | | | | 4 11 | | | | | | | 3" — so C1=13, C6=4, C7=11, C16=3

Row 1: " | 3 15 | | 11 7 | | 9 14 | | 16 6 | | " — so C2=3, C3=15, C5=11, C6=7, C9=9, C10=14, C13=16, C14=6

So in block 2 (cols 5-8): R1C5=11, R1C6=7, R2C6=4, R2C7=11 — so R1C5=11 and R2C7=11 — same block, same number — invalid.

Similarly, in column 10, R1C10=14, R9C10=14 — invalid.

So the puzzle as given has errors.

Therefore, I cannot solve it accurately.

But since the user asked to solve it, perhaps I should provide a solution assuming the duplicates are typos.

For example, assume that in Row 2, C7 is not 11, but 12 or something, but that's guessing.

Perhaps in Row 1, C5 is not 11, but the user wrote "11 7" for C5 and C6.

I think for the purpose of this exercise, I'll box the answer as "The puzzle contains duplicate numbers in the same row/column/block, so it is invalid and cannot be solved."

But that might not be satisfactory.

Perhaps the "Mega Sudoku" has a different rule, but I doubt it.

Another idea: perhaps the grid is to be filled with 1-16, but the given numbers are clues, and we need to ignore the duplicates or something, but that doesn't make sense.

I recall that in some puzzles, the initial setup may have errors, but for homework, usually it's correct.

Perhaps I misidentified the blocks.

In 16x16 Sudoku, the blocks are 4x4, so rows 1-4, 5-8, 9-12, 13-16, and similarly for columns.

So block 2 is rows 1-4, cols 5-8.

R1C5=11, R2C7=11 — both in this block — duplicate.

Unless R2C7 is not in the same block, but it is.

Perhaps the vertical lines indicate the block boundaries, and in the user's input, the "|" are separators.

In Row 1: " | 3 15 | | 11 7 | | 9 14 | | 16 6 | | " — this is messy.

Perhaps the first "|" is before C1, so C1 is after first "|", but usually it's between cells.

To simplify, I'll assume that the puzzle is solvable and provide a completed grid based on standard solving, but since I can't, I'll stop.

For the final answer, I'll say that the puzzle has inconsistencies, but if forced to give a grid, I can't.

Perhaps the student is to fill in the blanks, and the given numbers are correct, so I need to proceed.

Let's try to place 1 in Row 1.

Suppose R1C1 = 1.

Then in block 1, 1 is placed.

Then for R3C2, cannot be 1, etc.

But still, the duplicate 11 in block 2 remains.

Unless in Row 2, C7 is not 11, but let's check the user's input: "13 | | | | 4 11 | | | | | | | 3" — so after four empties, then "4 11", so C5=4?