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 A255920 #12 Sep 27 2015 09:40:48
%S A255920 0,0,0,1,0,1,1,1,1,0,0,1,0,0,0,2,2,3,0,1,1,1,1,1,2,1,3,1,1,1,1,1,0,1,
%T A255920 0,2,1,0,2,2,1,1,1,1,1,0,1,2,1,2,0,3,1,1,0,2,0,0,1,1,2,2,1,2,0,2,3,2,
%U A255920 1,2,0,2,1,2,2,1,1,1,3,2,2,0,0,1,0,0,0
%N A255920 Number of primes p with p < n such that n^(p-1) == 1 (mod p^2) i.e., number of Wieferich primes to base n less than n.
%H A255920 Felix Fröhlich, <a href="/A255920/b255920.txt">Table of n, a(n) for n = 2..9999</a>
%t A255920 f[n_] := Block[{p = Complement[Prime@ Range@ PrimePi@ n, First /@ FactorInteger@ n]}, Select[p, Divisible[n^(# - 1) - 1, #^2] &]]; Length /@ Table[f@ n, {n, 2, 120}] (* _Michael De Vlieger_, Sep 24 2015 *)
%o A255920 (PARI) for(n=2, 120, i=0; forprime(p=1, n, if(Mod(n, p^2)^(p-1)==1, i++)); print1(i, ", "))
%Y A255920 Cf. A242830.
%K A255920 nonn
%O A255920 2,16
%A A255920 _Felix Fröhlich_, Mar 11 2015