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 A328417 #8 Oct 18 2019 17:07:01 %S A328417 1,2,6,30,78,210,690,1050,4830 %N A328417 Numbers k such that A328412(k) sets a new record; numbers k such that (Z/mZ)* = C_2 X C_(2k) has more solutions for m than all k' < k, where (Z/mZ)* is the multiplicative group of integers modulo m. %C A328417 Conjecture: this sequence is infinite. That is to say, A328412 is unbounded. %C A328417 It seems that a(n) == 2 (mod 4) for n > 1. %H A328417 Wikipedia, <a href="https://en.wikipedia.org/wiki/Multiplicative_group_of_integers_modulo_n">Multiplicative group of integers modulo n</a> %e A328417 For k = 30: (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 30 is a term. %o A328417 (PARI) my(t=0); for(k=1, 5000, if(A328412(k)>t, print1(k, ", "); t=A328412(k))) \\ See A328412 for its program %Y A328417 Cf. A328412, A328418. %K A328417 nonn,hard,more %O A328417 1,2 %A A328417 _Jianing Song_, Oct 14 2019