Prime Friends
(Published on 14. November 2024, 05:10 by thoughtbyte)
Normal 6x6 Sudoku rules apply.
A cell is friendly if it contains its row, column, or box number. If a cell is friendly, its row and column numbers must sum to a prime number. Digits cannot repeat along the marked diagonal.
SudokuPad: https://sudokupad.app/0ub6jw7i7c
Solution code: Row 1.
Comments
on 21. January 2025, 02:54 by goldennumber
V nice 5 min solve if you understand the consequence of the ruleset. Surprised how well it works out! Well constructed
on 20. January 2025, 17:45 by Montikulum
Demanding and very rewarding at the same time!
on 16. November 2024, 07:32 by Playmaker6174
That was a fun and rather quick puzzle, thanks! Nice discovery there too :)
on 15. November 2024, 20:56 by Wonderment
Absolutely underrated puzzle. Sad that most will miss it because the rating has dropped below 90%. It is really awesome.
@Eloi.blok
As dzamie wrote, the rules do not state that all cells with r+c prime are friendly. So there can be less than 4 friendly cells in box 1.
on 15. November 2024, 00:18 by dzamie
I'm really impressed this works out to a unique solution! Also had to keep reminding myself that friendly number means prime box, but prime box does not mean friendly number.
on 14. November 2024, 19:57 by Eloi.blok
I have a problem in bix 1 I find 4 friendly cells, r1c1=2 r1c2=3 r2c1=3 r3c2=5, has there are 4 friendly celks buecause the sum of r+c is a prime number, i only can write the numbers 1, 2 and 3, so i don t find the 4th number that can be a friendly cell. I hope i explained it well :-)
on 14. November 2024, 15:07 by faltenin
That was fun! I had to be careful after some coloring and spacing possible digits to not "identify pairs and triples" - hold back the instincts and really think about the rule set.
on 14. November 2024, 05:46 by pms_headache
Took a sec to wrap my head around the rule set implications, but then flowed nicely. Fun puzzle. Thanks
