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 A255209 #16 Mar 07 2015 15:34:08 %S A255209 5107,20771,51427,52517,61417,66161,116731,119359,128657,140741, %T A255209 147647,150559,199783,203773,213949,229939,237283,261761,286751, %U A255209 288929,303089,339139,342373,381853,384611,385657,475897 %N A255209 Primes p for which exactly six bases b with 1 < b < p exist such that p is a base b Wieferich prime. %C A255209 p = prime(n) such that A242830(n) = 6. %H A255209 R. Fischer, <a href="http://www.fermatquotient.com/FermatQuotienten/ErstBasen.txt">Thema: Fermatquotient B^(P-1) == 1 (mod P^2) Fermatquotienten mit extremen Erst-Basen</a> %o A255209 (PARI) forprime(p=1, , b=2; i=0; while(b < p, if(Mod(b, p^2)^(p-1)==1, i++); b++); if(i==6, print1(p, ", "))) %Y A255209 Cf. A255203, A255204, A255205, A255206, A255207, A255208, A255210. %K A255209 nonn,more %O A255209 1,1 %A A255209 _Felix Fröhlich_, Feb 17 2015