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 A367715 #7 Nov 28 2023 08:50:49
%S A367715 1,2,4,8,16,33,68,140,288,594,1225,2526,5208,10740,22148,45673,94184,
%T A367715 194224,400524,825950,1703249,3512395,7243168,14936668,30801992,
%U A367715 63519044,130987274,270118452,557031032,1148694482,2368807011,4884890405,10073490200
%N A367715 G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - x * (1 + x + x^2 + x^3) * A(x^4))).
%F A367715 a(n) = 1 + Sum_{k=0..n-1} a(floor(k/4)) * a(n-1-k).
%o A367715 (PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, i-1, v[j\4+1]*v[i-j])); v;
%Y A367715 Cf. A367713, A367714.
%Y A367715 Cf. A367657, A367692.
%K A367715 nonn
%O A367715 0,2
%A A367715 _Seiichi Manyama_, Nov 28 2023