This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A255208 #9 Mar 07 2015 15:33:48 %S A255208 653,4909,7723,9811,13691,15413,18133,18223,21061,22147,25679,29131, %T A255208 33923,35353,36913,37633,46021,57527,61819,66107,71059,72643,77867, %U A255208 79867,85061,87509,89113,96757,97213,98641,117977,118163,120247,122209,123653,126443,129061 %N A255208 Primes p for which exactly five bases b with 1 < b < p exist such that p is a base b Wieferich prime. %C A255208 p = prime(n) such that A242830(n) = 5. %o A255208 (PARI) forprime(p=1, , b=2; i=0; while(b < p, if(Mod(b, p^2)^(p-1)==1, i++); b++); if(i==5, print1(p, ", "))) %Y A255208 Cf. A255203, A255204, A255205, A255206, A255207, A255209, A255210. %K A255208 nonn %O A255208 1,1 %A A255208 _Felix Fröhlich_, Feb 17 2015