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 A366456 #12 Oct 10 2023 16:23:42
%S A366456 1,2,-7,56,-532,5600,-62860,737324,-8929726,110811344,-1401640814,
%T A366456 18004922936,-234243536436,3080152906096,-40870739065996,
%U A366456 546563064528906,-7358930622768977,99672580921800656,-1357142384455626909,18565841939010374736,-255054402946387767408
%N A366456 G.f. A(x) satisfies A(x) = 1 + x + x/A(x)^(7/2).
%F A366456 G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A366402.
%F A366456 a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(9*k/2-1,k) * binomial(n+7*k/2-2,n-k) / (9*k/2-1).
%o A366456 (PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(9*k/2-1, k)*binomial(n+7*k/2-2, n-k)/(9*k/2-1));
%Y A366456 Cf. A112478, A364393, A364407, A364408, A364409, A366266, A366267, A366268, A366452, A366453, A366454, A366455.
%Y A366456 Cf. A366402.
%K A366456 sign
%O A366456 0,2
%A A366456 _Seiichi Manyama_, Oct 10 2023