A366087 Expansion of (1/x) * Series_Reversion( x*(1-x)/(1-x-x^4) ).
1, 0, 0, 0, -1, -1, -1, -1, 3, 8, 14, 21, 7, -40, -134, -291, -389, -188, 710, 2906, 6285, 8931, 5477, -15250, -66359, -149426, -224524, -154288, 336695, 1605033, 3774375, 5887736, 4504451, -7603388, -40495514, -98834842, -159804251, -134317549, 173843349, 1050099387
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n\4, (-1)^k*binomial(n+1, k)*binomial(n-3*k-1, n-4*k))/(n+1);
Formula
a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(n+1,k) * binomial(n-3*k-1,n-4*k).