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A364764
G.f. satisfies A(x) = 1 + x*A(x)^2 / (1 + x*A(x)^4).
3
1, 1, 1, -2, -14, -27, 70, 625, 1457, -3541, -37403, -98547, 207098, 2564079, 7448923, -12940485, -190014459, -600991549, 827159379, 14802832468, 50584687754, -52159768068, -1193457862093, -4384199208207, 3090291576246, 98618925147291, 388126462227091
OFFSET
0,4
FORMULA
a(n) = (1/n) * Sum_{k=0..n-1} (-1)^k * binomial(n,k) * binomial(2*n+2*k,n-1-k) for n > 0.
PROG
(PARI) a(n) = if(n==0, 1, sum(k=0, n-1, (-1)^k*binomial(n, k)*binomial(2*n+2*k, n-1-k))/n);
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 05 2023
STATUS
approved