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 A328418 #7 Oct 18 2019 17:07:11 %S A328418 2,4,7,11,12,13,15,16,23 %N A328418 Records in A328412. %C A328418 Companion sequence of A328417. %C A328418 Conjecture: this sequence is infinite. That is to say, A328412 is unbounded. %H A328418 Wikipedia, <a href="https://en.wikipedia.org/wiki/Multiplicative_group_of_integers_modulo_n">Multiplicative group of integers modulo n</a> %e A328418 Let (Z/mZ)* be the multiplicative group of integers modulo m. We have (Z/mZ)* = C_2 X C_60 has 11 solutions, namely m = 143, 155, 175, 183, 225, 244, 286, 310, 350, 366, 450; for all k' < 30, (Z/mZ)* = C_2 X C_(2k') has fewer than 11 solutions. So A328412(30) = 11 is a term. %o A328418 (PARI) my(t=0); for(k=1, 5000, if(A328412(k)>t, print1(a(k), ", "); t=A328412(k))) %Y A328418 Cf. A328412, A328417. %K A328418 nonn,hard,more %O A328418 1,1 %A A328418 _Jianing Song_, Oct 14 2019