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 A367049 #11 Nov 03 2023 11:18:33
%S A367049 1,1,5,28,187,1361,10479,83914,691738,5830903,50028259,435454040,
%T A367049 3835732631,34128555184,306276957665,2769050552948,25197515469820,
%U A367049 230599623819217,2121066298440282,19597929365099640,181814132152022195,1692920612932871541
%N A367049 G.f. satisfies A(x) = 1 + x*A(x)^4 + x^2*A(x)^2.
%F A367049 a(n) = Sum_{k=0..floor(n/2)} binomial(3*n-4*k+1,k) * binomial(4*n-6*k,n-2*k)/(3*n-4*k+1).
%o A367049 (PARI) a(n) = sum(k=0, n\2, binomial(3*n-4*k+1, k)*binomial(4*n-6*k, n-2*k)/(3*n-4*k+1));
%Y A367049 Cf. A365178, A365180, A365181, A365182, A365183, A367041, A367048, A367050.
%K A367049 nonn
%O A367049 0,3
%A A367049 _Seiichi Manyama_, Nov 03 2023