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 A364067 #21 Jul 07 2023 06:38:11
%S A364067 0,1,0,3,0,4,0,5,2,6,0,7,0,13,0,9,0,10,6,11,0,15,0,20,0,14,0,15,8,23,
%T A364067 0,17,0,27,0,19,0,28,10,21,4,22,0,34,0,33,0,25,12,26,0,36,0,51,0,29,0,
%U A364067 30,14,31,0,43,10,48,0,39,0,35,16,48,0,37,0,66,0,39,0,53,18,52,0,42,0,62,12,58,0,45
%N A364067 Expansion of Sum_{k>0} k * x^(2*k) / (1 - x^(3*k-1)).
%H A364067 Seiichi Manyama, <a href="/A364067/b364067.txt">Table of n, a(n) for n = 1..10000</a>
%F A364067 a(n) = (1/3) * Sum_{d | 3*n-2, d==2 (mod 3)} (d+1).
%F A364067 G.f.: Sum_{k>0} x^(2*k) / (1 - x^(3*k-1))^2.
%t A364067 a[n_] := DivisorSum[3*n - 2, # + 1 &, Mod[#, 3] == 2 &]/3; Array[a, 100] (* _Amiram Eldar_, Jul 05 2023 *)
%o A364067 (PARI) a(n) = sumdiv(3*n-2, d, (d%3==2)*(d+1))/3;
%Y A364067 Cf. A359239, A363891.
%Y A364067 Cf. A364064, A364065, A364066.
%K A364067 nonn
%O A364067 1,4
%A A364067 _Seiichi Manyama_, Jul 04 2023