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 A305333 #6 Jun 07 2018 22:03:39 %S A305333 1,2,1,4,1,1,16 %N A305333 Let p be the n-th base-5 Wieferich prime (A123692). a(n) is the value of p-1 divided by the multiplicative order of 5 (mod p^2). %F A305333 a(n) = (A123692(n)-1)/A305332(n). %o A305333 (PARI) v=[2, 20771, 40487, 53471161, 1645333507, 6692367337, 188748146801]; for(k=1, #v, my(ord=znorder(Mod(5, v[k]^2))); print1((v[k]-1)/ord, ", ")) %Y A305333 Cf. A123692, A211241, A305331, A305332. %K A305333 nonn,hard,more %O A305333 1,2 %A A305333 _Felix Fröhlich_, May 30 2018