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 A367062 #10 Nov 04 2023 10:11:58
%S A367062 1,1,3,13,64,339,1889,10917,64836,393292,2426335,15176847,96029114,
%T A367062 613540477,3952727925,25649572693,167494312692,1099850119488,
%U A367062 7257905610260,48106858236044,320131295055690,2138010763838375,14325505944147495,96273042489762471
%N A367062 G.f. satisfies A(x) = 1 + x*A(x)^3 + x^3*A(x)^6.
%F A367062 a(n) = (1/(2*n+1)) * Sum_{k=0..floor(n/3)} binomial(2*n+1,k) * binomial(3*n-3*k,n-3*k).
%o A367062 (PARI) a(n) = sum(k=0, n\3, binomial(2*n+1, k)*binomial(3*n-3*k, n-3*k))/(2*n+1);
%Y A367062 Cf. A366676, A367057, A367058, A367059, A367060, A367061.
%K A367062 nonn
%O A367062 0,3
%A A367062 _Seiichi Manyama_, Nov 04 2023