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 A334212 #16 Jun 04 2020 13:11:37 %S A334212 3,1,5,3,7,1,1,5,11,1,10,7,3,1,17,1,2,1,3,11,10,1,1,13,1,1,10,3,31,1, %T A334212 2,10,5,1,37,10,2,1,5,2,10,1,1,21,47,1,1,1,3,1,10,1,5,1,3,2,10,1,14, %U A334212 21,1,1,5,3,21,1,2,3,2,1,10,10,1,1,7,3,10,1 %N A334212 Least number k such that n^k + 1 is not squarefree. %C A334212 For n == 1 (mod 4) (n not 1), a(n) <= (n + 1)/2. %C A334212 For n == 3 (mod 4), a(n) = 1. %C A334212 For even n, a(n) <= n + 1. %C A334212 Existence proof for n >= 2 and upper bounds use the binomial formula. %o A334212 (PARI) for(n=2,79, for(k=1,n+1, !issquarefree(n^k+1)&!print1(k", ")&break)) %Y A334212 Cf. A013929, A334213, A334214. %K A334212 nonn %O A334212 2,1 %A A334212 _Gionata Neri_, Apr 18 2020