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 A363973 #14 Jun 30 2023 15:36:28
%S A363973 0,0,1,0,0,1,4,0,1,0,9,1,0,4,17,0,0,1,25,0,5,9,36,1,0,0,50,4,0,17,64,
%T A363973 0,10,0,85,1,0,25,101,0,0,5,121,9,17,36,144,1,4,0,170,0,0,50,205,4,26,
%U A363973 0,225,17,0,64,261,0,0,10,289,0,37,85,324,1,0,0,378,25,13,101,400,0,50,0
%N A363973 Expansion of Sum_{k>0} k^2 * x^(4*k-1) / (1 - x^(4*k-1)).
%F A363973 a(n) = Sum_{d|n, d==3 mod 4} ((d+1)/4)^2.
%t A363973 a[n_] := DivisorSum[n, ((#+1)/4)^2 &, Mod[#, 4] == 3 &]; Array[a, 100] (* _Amiram Eldar_, Jun 30 2023 *)
%o A363973 (PARI) a(n) = sumdiv(n, d, (d%4==3)*((d+1)/4)^2);
%Y A363973 Cf. A001842, A363904.
%Y A363973 Cf. A050453, A363978.
%K A363973 nonn,easy
%O A363973 1,7
%A A363973 _Seiichi Manyama_, Jun 30 2023