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A364473
G.f. satisfies A(x) = 1 + x*A(x)^2 + x^2*A(x)^6.
1
1, 1, 3, 13, 65, 353, 2024, 12057, 73890, 462851, 2950261, 19073921, 124776881, 824409052, 5493384031, 36874564529, 249114808794, 1692489908494, 11556616157589, 79265016880139, 545860966841247, 3772800724433931, 26162662010039826, 181974370638420829
OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..floor(n/2)} binomial(2*n+2*k,k) * binomial(2*n+k,n-2*k) / (n+3*k+1).
PROG
(PARI) a(n) = sum(k=0, n\2, binomial(2*n+2*k, k)*binomial(2*n+k, n-2*k)/(n+3*k+1));
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 26 2023
STATUS
approved