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 A367112 #9 Nov 05 2023 09:01:12
%S A367112 1,2,4,9,24,72,227,730,2384,7916,26704,91280,315319,1098710,3856948,
%T A367112 13628441,48435808,173030048,620965396,2237681720,8093572960,
%U A367112 29372735368,106925552672,390336084256,1428620011263,5241166583502,19270575881964
%N A367112 G.f. satisfies A(x) = 1 + 2*x*A(x) + x^3*A(x)^3.
%F A367112 a(n) = Sum_{k=0..floor(n/3)} 2^(n-3*k) * binomial(n,3*k) * A001764(k).
%o A367112 (PARI) a(n) = sum(k=0, n\3, 2^(n-3*k)*binomial(n, 3*k)*binomial(3*k, k)/(2*k+1));
%Y A367112 Cf. A001764, A071879, A367111, A367113.
%Y A367112 Cf. A367073.
%K A367112 nonn,easy
%O A367112 0,2
%A A367112 _Seiichi Manyama_, Nov 05 2023