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URL: https://oeis.org/A368934

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A368934
Expansion of (1/x) * Series_Reversion( x * (1-x)^2 * (1-x-x^2) ).
1
1, 3, 16, 104, 751, 5789, 46656, 388377, 3313304, 28816513, 254548840, 2277498340, 20596833817, 187974816142, 1729033498416, 16012809644088, 149186508912927, 1397300099214753, 13149137686976324, 124262625068365924, 1178796712807563025
OFFSET
0,2
FORMULA
a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} binomial(n+k,k) * binomial(4*n-k+2,n-2*k).
PROG
(PARI) a(n) = sum(k=0, n\2, binomial(n+k, k)*binomial(4*n-k+2, n-2*k))/(n+1);
(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*(1-x)^2*(1-x-x^2))/x)
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jan 10 2024
STATUS
approved