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 A374064 #6 Jun 27 2024 10:19:26
%S A374064 1,0,-1,0,1,-1,-1,1,0,-1,1,0,-1,1,0,-2,2,1,-3,1,3,-3,0,3,-3,-1,4,-3,
%T A374064 -1,5,-3,-3,7,-3,-5,7,-1,-7,8,0,-8,8,1,-11,10,3,-14,9,8,-17,8,10,-18,
%U A374064 6,14,-22,6,19,-24,1,26,-26,-3,30,-25,-9,37,-27,-13,42,-26,-23,51,-25,-31,56
%N A374064 Expansion of Product_{k>=1} 1 / (1 + x^(3*k-1)).
%F A374064 a(0) = 1; a(n) = -Sum_{k=1..n} A262928(k) * a(n-k).
%F A374064 a(n) = Sum_{k=0..n} A081362(k) * A132463(n-k).
%F A374064 a(n) = Sum_{k=0..n} A109389(k) * A261612(n-k).
%t A374064 nmax = 75; CoefficientList[Series[Product[1/(1 + x^(3 k - 1)), {k, 1, nmax}], {x, 0, nmax}], x]
%t A374064 a[0] = 1; a[n_] := a[n] = (1/n) Sum[DivisorSum[k, (-1)^(k/#) # &, Mod[#, 3] == 2 &] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 75}]
%Y A374064 Cf. A035386, A081360, A081362, A109389, A132463, A261612, A262928, A284315, A374065.
%K A374064 sign
%O A374064 0,16
%A A374064 _Ilya Gutkovskiy_, Jun 27 2024