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 A367691 #9 Nov 27 2023 07:56:58
%S A367691 1,2,3,4,7,12,19,31,52,86,141,233,386,639,1057,1749,2896,4795,7937,
%T A367691 13138,21751,36010,59613,98688,163380,270479,447779,741300,1227231,
%U A367691 2031697,3363494,5568295,9218373,15261119,25264942,41826373,69244006,114634194,189778123
%N A367691 G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - x * A(x^3))).
%F A367691 a(n) = 1 + Sum_{k=0..floor((n-1)/3)} a(k) * a(n-1-3*k).
%o A367691 (PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, (i-1)\3, v[j+1]*v[i-3*j])); v;
%Y A367691 Cf. A007317, A351972, A367692.
%Y A367691 Cf. A367659.
%K A367691 nonn
%O A367691 0,2
%A A367691 _Seiichi Manyama_, Nov 27 2023