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 A366406 #10 Oct 09 2023 11:20:32
%S A366406 1,2,-5,44,-383,3782,-39653,434324,-4910009,56862170,-671131131,
%T A366406 8043570088,-97629201137,1197607836678,-14824033357867,
%U A366406 184923041147906,-2322472423266102,29341825623660226,-372652945642370654,4755048678561786946,-60929667733382420198
%N A366406 G.f. A(x) satisfies A(x) = (1 + x / A(x)^(7/2)) / (1 - x).
%F A366406 a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(9*k/2-1,k) * binomial(7*k/2-1,n-k) / (9*k/2-1).
%o A366406 (PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(9*k/2-1, k)*binomial(7*k/2-1, n-k)/(9*k/2-1));
%Y A366406 Cf. A366400, A366401, A366402, A366403, A366404, A366405, A366407.
%K A366406 sign
%O A366406 0,2
%A A366406 _Seiichi Manyama_, Oct 09 2023