Re:Mathematicians Outwit Hidden Number Conspiracy
by tzs on Tuesday January 04, 2022 @03:44PM
(#29800180)
You are right. To fix mine, I'd need to take into account the actual endpoints of the interval instead of just the length of the interval. For each divisor d there would be a separate case to consider for each possible value of 10n mod d. This seems like it would greatly complicate my approach.
[521, 523, 527, 529, 533, 541, 547, 551, 557, 559, 563, 569, 571, 577, 583, 587, 589, 593, 599, 601, 607, 611, 613, 617, 619]
You really need to use all the primes from 2 to 13 inclusive to get a limit of 23. And even then I was only able to prove it by brute-forcing up to the primorial of 13, but maybe there's a simpler way.