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 A195864 #26 May 21 2025 06:34:39
%S A195864 3,14,15,168,326,5414,33357341,4324809536
%N A195864 Numbers k such that sigma(k) + tau(k) is a perfect number (A000396).
%C A195864 A002093(848) < a(9) <= 1155321467378283328. - _Donovan Johnson_, Nov 03 2011
%t A195864 perfect = {6, 28, 496, 8128, 33550336, 8589869056, 137438691328}; Select[Range[10000], MemberQ[perfect, DivisorSigma[0, #] + DivisorSigma[1, #]] &] (* _T. D. Noe_, Nov 03 2011 *)
%Y A195864 Cf. A000396, A002093, A007503 (sigma(n) + tau(n)).
%K A195864 nonn,more
%O A195864 1,1
%A A195864 _Jeff Kruse_, Oct 26 2011
%E A195864 a(8) from _Donovan Johnson_, Nov 03 2011