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 A368688 #5 Jan 03 2024 09:28:53
%S A368688 1,2,2,4,4,7,7,13,15,24,29,50,61,96,134,202,278,426,596,898,1286,1903,
%T A368688 2746,4082,5900,8703,12679,18658,27202,40023,58426,85828,125521,
%U A368688 184195,269552,395502,578950,849088,1243586,1823380,2670965,3915867,5736962,8409830,12322560,18062121,26467300,38793983,56849093
%N A368688 Expansion of g.f. Sum_{n>=1} q^n/(1-q^n-q^(3*n)).
%o A368688 (PARI) my(N=55, q='q+O('q^N)); Vec(sum(n=1,N,q^n/(1-q^n-q^(3*n))))
%Y A368688 Cf. A007435 (g.f. Sum{n>=1} q^n/(1-q^n-q^(2*n))), A368689 (g.f. Sum_{n>=1} q^n/(1-q^(2*n)-q^(3*n))), A368687 (g.f. Sum_{n>=1} q^n/(1-q^n-q^(2*n)-q^(3*n))).
%K A368688 nonn
%O A368688 1,2
%A A368688 _Joerg Arndt_, Jan 03 2024