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 A074388 #16 Aug 13 2024 05:31:14
%S A074388 195938,224450,13645088,15870978,18180450,29184800,1105252128,
%T A074388 2363968800,2686005218,2917410498,3564550178,5056357922,8442721568,
%U A074388 10814792450,18587462432,21292224800,48666384162,140836104992,212352534818,217566422658,288728564418,315325993248
%N A074388 Numbers of the form 2*k^2 such that sigma(2*k^2) is an odd square.
%C A074388 No terms whose sum of divisors is a square of a prime below 10^12 were found.
%H A074388 Amiram Eldar, <a href="/A074388/b074388.txt">Table of n, a(n) for n = 1..200</a> (calculated using the b-file at A097023)
%F A074388 a(n) = 2*A097023(n)^2. - _Amiram Eldar_, Aug 13 2024
%e A074388 195938 = 2*313^2 and sigma(195938) = 294849 = 543^2.
%t A074388 Do[s=DivisorSigma[1, 2*(n^2)]; If[IntegerQ[Sqrt[s]]&&Mod[s, 2]==1, Print[2*(n^2)]], {n, 1, 10000000}]
%Y A074388 Cf. A000203, A001248, A028982, A074386, A097023.
%K A074388 nonn
%O A074388 1,1
%A A074388 _Labos Elemer_, Aug 22 2002
%E A074388 a(19)-a(22) from _Amiram Eldar_, Aug 13 2024