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 A365267 #10 Aug 30 2023 07:29:55
%S A365267 1,1,2,5,15,47,153,513,1763,6177,21981,79224,288611,1061019,3931320,
%T A365267 14666135,55041855,207668702,787225265,2996851140,11452198368,
%U A365267 43915195973,168930713580,651708006690,2520840672423,9774511167507,37985839339052
%N A365267 G.f. satisfies A(x) = 1 + x*A(x)^2*(1 + x^3*A(x)).
%F A365267 a(n) = Sum_{k=0..floor(n/4)} binomial(n-3*k,k) * binomial(2*n-5*k+1,n-3*k)/(2*n-5*k+1).
%o A365267 (PARI) a(n) = sum(k=0, n\4, binomial(n-3*k, k)*binomial(2*n-5*k+1, n-3*k)/(2*n-5*k+1));
%Y A365267 Cf. A001002, A071969.
%Y A365267 Cf. A063021, A365268.
%K A365267 nonn
%O A365267 0,3
%A A365267 _Seiichi Manyama_, Aug 30 2023