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 A366081 #15 Sep 30 2023 09:18:45
%S A366081 1,1,1,0,-5,-22,-68,-165,-285,-96,1892,10574,38436,107175,217063,
%T A366081 165232,-1150565,-7780744,-31173680,-94537100,-212903852,-239418048,
%U A366081 788015576,6734057510,29396759220,95418332383,233697161887,334222633632,-514863450175,-6299672869750
%N A366081 Expansion of (1/x) * Series_Reversion( x*(1-x)^2/(1-x-x^2) ).
%H A366081 Seiichi Manyama, <a href="/A366081/b366081.txt">Table of n, a(n) for n = 0..1000</a>
%F A366081 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} (-1)^k * binomial(n+1,k) * binomial(2*n-k,n-2*k).
%o A366081 (PARI) a(n) = sum(k=0, n\2, (-1)^k*binomial(n+1, k)*binomial(2*n-k, n-2*k))/(n+1);
%Y A366081 Cf. A007440, A108623, A366082, A366083.
%Y A366081 Cf. A109081.
%K A366081 sign
%O A366081 0,5
%A A366081 _Seiichi Manyama_, Sep 28 2023