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 A344974 #13 Jun 12 2021 06:06:16
%S A344974 1,2,3,4,5,6,7,8,9,10,11,13,16,17,18,19,21,23,24,25,26,27,28,29,31,32,
%T A344974 34,36,37,39,40,41,43,47,49,50,53,55,57,58,59,61,64,67,68,71,73,74,75,
%U A344974 78,79,81,82,83,89,93,96,97,98,100,101,103,106,107,109,111,113,120,121,122,125,127,128,129,131,136,137
%N A344974 Numbers k such that A011772(k) divides A344875(k).
%t A344974 A011772[n_] := Module[{m = 1}, While[Not[IntegerQ[m(m+1)/(2n)]], m++]; m];
%t A344974 A344875[n_] := Product[{p, e} = pe; If[p == 2, 2^(1+e)-1, p^e-1], {pe, FactorInteger[n]}];
%t A344974 Select[Range[200], Divisible[A344875[#], A011772[#]]&] (* _Jean-François Alcover_, Jun 12 2021 *)
%o A344974 (PARI) isA344974(n) = (0==A344973(n));
%Y A344974 Cf. A011772, A344875, A344884 (characteristic function).
%Y A344974 Positions of ones in A344970, of zeros in A344973.
%Y A344974 Union of A000961 and A344975. Complement of A344980.
%Y A344974 Cf. also A344595 (subsequence).
%K A344974 nonn
%O A344974 1,2
%A A344974 _Antti Karttunen_, Jun 04 2021