The Subprimes Fiasco
(Published on 21. March 2023, 09:11 by Farkov)
Rules:
Normal sudoku rules apply.
Digits along a thermometer must increase from the bulb end (R9C5 is on a thermometer).
Every row and column consists of 4 2-digit and 1 1-digit numbers. If these numbers are greater than 50 they must be prime, if they are less than 50 they must not be prime.
All cells that contain a 1-digit number are highlighted with a square.
It is up to you to ascertain whether a 1-digit square is being used for the row or the column (or both).
Disambiguities:
1 is not a prime number.
Some rows/columns have more than one possible 1-digit square. For example take the row 619732845. This has two legal combinations: 61, 97, 32, 8, 45; and 61, 9, 73, 28, 45. In this case both 8 and 9 may be highlighted as 1-digit cells.
Feedback always appreciated. Good luck :)
F-puzzles link.
Hints:
I'm not usually a "mark all possibilities" kinda guy, but in this puzzle I find it helps a lot.
If you know your 12 times tables (which is what I was taught in school) then the only unusual number you need to know outside of that is 91 (13*7).
A handy rule for checking to see if something is a multiple of 3 is to add the digits together and then check to see if the result is a mulitple of 3. For example 57 = 5+7=12. And 12 is a multiple of 3. (Or add 1+2 together as well to get 3, hehe).
Solution code: Row 5, column 5.
Comments
on 27. August 2023, 10:07 by Bankey
Abandoned this on two earlier attempts, but got thru the third time! Brutal, but amazing puzzle. Thanks, @ Farkov :).
on 18. April 2023, 12:46 by bodemeister
Taking another look at the puzzle and want to make sure numbers must be read from left to right in rows and from top to bottom in columns.
@bodemeister Yes, 100%.
on 27. March 2023, 23:23 by Bonehead
That was rock hard but absolutely brilliantly conceived. Thanks to me mixing up a vertical/horizontal single early on it took me 3 hours to find the mistake and re-do, but I got there. More folk deserve to try this.
@Bonehead I feel you might be a bit more intelligent than your average bonehead. Congrats on the solve and thanks for your kind words :)
on 23. March 2023, 13:06 by Farkov
I fixed the example given. Thank you bodemeister :)
on 23. March 2023, 09:15 by bodemeister
This looks like a fun puzzle! Just to clarify, in your example should the first combination end with 46 and 38? Also in your example would 25 97 1 46 38 be a legal combination?
@bodemeister Very well spotted. Thank you very much, I will fix that now. How did I ever manage to mess up the *example*? :)
on 21. March 2023, 14:28 by StefanSch
Absolute impressiv and amazing! I can't imagine, how to construct such a puzzle.
@StefanSch Thanks for giving it a go Stefan. Glad you liked it :)
on 21. March 2023, 09:11 by Farkov
After solving the Aad van de Wetering puzzle featuring 2-digit primes on CTC yesterday I was reminded that I'd been saving this puzzle up for a special occasion. I guess Tuesday is as special an occasion as any.
