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 A363259 #14 Jul 08 2023 08:05:14
%S A363259 0,1,0,2,1,3,0,5,0,5,3,6,0,8,0,8,4,11,0,11,0,11,5,12,2,14,0,17,6,15,0,
%T A363259 19,0,17,7,18,0,24,5,20,8,21,0,23,0,25,9,29,0,29,0,26,16,27,0,29,0,35,
%U A363259 11,32,3,32,0,32,12,33,7,46,0,35,13,39,0,40,0,38,14,47,0,41,8,41,22,42,0,49,0
%N A363259 Expansion of Sum_{k>0} k * x^(2*k) / (1 - x^(4*k-1)).
%F A363259 a(n) = (1/4) * Sum_{d | 4*n-2, d==3 (mod 4)} (d+1).
%F A363259 G.f.: Sum_{k>0} x^(3*k-1) / (1 - x^(4*k-2))^2.
%t A363259 a[n_] := DivisorSum[4*n - 2, # + 1 &, Mod[#, 4] == 3 &]/4; Array[a, 100] (* _Amiram Eldar_, Jul 08 2023 *)
%o A363259 (PARI) a(n) = sumdiv(4*n-2, d, (d%4==3)*(d+1))/4;
%Y A363259 Cf. A364084, A364085.
%Y A363259 Cf. A363392.
%K A363259 nonn
%O A363259 1,4
%A A363259 _Seiichi Manyama_, Jul 08 2023