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A368937
Expansion of (1/x) * Series_Reversion( x * (1-x) * (1-x+x^5) ).
2
1, 2, 7, 30, 143, 727, 3861, 21165, 118845, 680064, 3951291, 23247874, 138229486, 829292780, 5013767772, 30516496017, 186837457296, 1149894814718, 7110026033305, 44146396259805, 275139524189497, 1720647439298395, 10793938343564655, 67905034046934225
OFFSET
0,2
FORMULA
a(n) = (1/(n+1)) * Sum_{k=0..floor(n/5)} (-1)^k * binomial(n+k,k) * binomial(3*n-4*k+1,n-5*k).
PROG
(PARI) a(n) = sum(k=0, n\5, (-1)^k*binomial(n+k, k)*binomial(3*n-4*k+1, n-5*k))/(n+1);
(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*(1-x)*(1-x+x^5))/x)
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jan 10 2024
STATUS
approved