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 A076619 #21 Feb 11 2021 03:32:17
%S A076619 3,3,4,7,3,7,11,7,6,4,15,3,7,11,23,16,7,8,11,27,7,15,31,22,3,35,7,16,
%T A076619 39,11,4,43,23,31,47,7,15,34,11,27,7,15,59,40,31,12,63,6,43,3,67,16,
%U A076619 35,71,7,22,75,31,39,52,79,11,7,83,43,14,58,87,36,23,31,47,95,22,7,15,67
%N A076619 Least x>1 such that x^d == 1 (mod d) for each divisor d of n, for all nonsquarefree numbers n (cf. A013929).
%C A076619 If n is squarefree (cf. A005117), then the least x>1 such that x^d == 1 (mod d) (for each divisor d of n) equals n+1.
%F A076619 a(p^m) = p+1 for p prime and m>1.
%F A076619 a(n) = A076618(A013929(n)). - _Michel Marcus_, Jul 13 2013
%F A076619 a(n) = A076333(n) + 1. - _Amiram Eldar_, Feb 11 2021
%t A076619 f[n_] := If[(r = Times @@ FactorInteger[n][[;; , 1]]) < n, r, 0]; Select[f /@ Range[200], # > 0 &] + 1 (* _Amiram Eldar_, Feb 11 2021 *)
%o A076619 (PARI) lista(nn) = {for(n=1, nn, if (!issquarefree(n), print1(A076618(n), ", ");););} \\ _Michel Marcus_, Jul 13 2013
%Y A076619 Cf. A013929, A076333, A076618 (sequence for all integers).
%K A076619 nonn
%O A076619 1,1
%A A076619 _Benoit Cloitre_, Oct 22 2002