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 A363258 #16 Jul 08 2023 08:05:18
%S A363258 1,1,3,1,4,1,5,3,6,1,7,1,10,4,9,1,10,3,11,5,12,1,18,1,14,6,15,3,16,1,
%T A363258 17,10,24,1,19,1,20,10,21,1,25,1,30,9,24,5,25,3,26,13,27,1,36,1,29,11,
%U A363258 30,3,38,6,32,12,42,1,34,1,35,18,36,1,37,5,48,20,39,1,48,3,41,15,42,1,54,1,48,19,45,10
%N A363258 Expansion of Sum_{k>0} k * x^(2*k-1) / (1 - x^(4*k-3)).
%F A363258 a(n) = (1/4) * Sum_{d | 4*n-2, d==1 (mod 4)} (d+3).
%F A363258 G.f.: Sum_{k>0} x^k / (1 - x^(4*k-2))^2.
%t A363258 a[n_] := DivisorSum[4*n - 2, # + 3 &, Mod[#, 4] == 1 &]/4; Array[a, 100] (* _Amiram Eldar_, Jul 08 2023 *)
%o A363258 (PARI) a(n) = sumdiv(4*n-2, d, (d%4==1)*(d+3))/4;
%Y A363258 Cf. A364082, A364083.
%Y A363258 Cf. A363316.
%K A363258 nonn
%O A363258 1,3
%A A363258 _Seiichi Manyama_, Jul 08 2023