A368793 a(n) = (3*n-2)!!! * Sum_{k=0..n} k/(3*k-2)!!!.

0, 1, 6, 45, 454, 5907, 94518, 1795849, 39508686, 987717159, 27656080462, 857338494333, 29149508807334, 1078531825871371, 43141273034854854, 1855074740498758737, 85333438062942901918, 4181338465084202193999, 217429600184378514087966

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Formula

a(0) = 0; a(n) = (3*n-2)*a(n-1) + n.

Prog

(PARI) a007559(n) = prod(k=1, n, 3*k-2);
a(n) = a007559(n)*sum(k=0, n, k/a007559(k));

Crossrefs

Cf. A007559, A368792.

Sequence in context: A331726 A084064 A186925 * A294642 A346682 A109516

Adjacent sequences: A368790 A368791 A368792 * A368794 A368795 A368796

Keyword

nonn

Author

Seiichi Manyama, Jan 05 2024

Status

approved