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 A378958 #21 Dec 13 2024 09:40:40
%S A378958 1,1,2,8,32,145,681,3337,16773,86181,450268,2385544,12784861,69189509,
%T A378958 377576512,2075423744,11480230037,63857579629,356962271136,
%U A378958 2004255583560,11298268724556,63919517790933,362806671879955,2065443363987045,11790688867079872,67477283970889867
%N A378958 G.f. A(x) satisfies A(x) = 1 + x/A(x) * (1 - A(x) + A(x)^4).
%F A378958 a(n) = (1/n) * Sum_{k=0..n} (-1)^k * binomial(n,k) * binomial(3*n-4*k,n-k-1) for n > 0.
%o A378958 (PARI) a(n) = if(n==0, 1, sum(k=0, n, (-1)^k*binomial(n, k)*binomial(3*n-4*k, n-k-1))/n);
%Y A378958 Cf. A317133, A364759, A377706, A377458, A378920.
%Y A378958 Cf. A367724.
%K A378958 nonn
%O A378958 0,3
%A A378958 _Seiichi Manyama_, Dec 12 2024