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A371539
G.f. A(x) satisfies A(x) = (1 + x*A(x)^(3/2) / (1+x))^4.
4
1, 4, 26, 224, 2171, 22600, 246754, 2787856, 32318849, 382266056, 4594893684, 55966343520, 689245218880, 8568130064280, 107371481352870, 1354944741505580, 17203182641794020, 219604431213873060, 2816826935574781930, 36286757255072528360, 469266638574298431490
OFFSET
0,2
FORMULA
a(n) = 4 * Sum_{k=0..n} (-1)^(n-k) * binomial(n-1,n-k) * binomial(6*k+4,k)/(6*k+4).
G.f.: A(x) = B(x)^4 where B(x) is the g.f. of A349362.
PROG
(PARI) a(n) = 4*sum(k=0, n, (-1)^(n-k)*binomial(n-1, n-k)*binomial(6*k+4, k)/(6*k+4));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 26 2024
STATUS
approved