A368793 - OEIS

%I #8 Jan 06 2024 09:21:56

%S 0,1,6,45,454,5907,94518,1795849,39508686,987717159,27656080462,

%T 857338494333,29149508807334,1078531825871371,43141273034854854,

%U 1855074740498758737,85333438062942901918,4181338465084202193999,217429600184378514087966

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

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

%o (PARI) a007559(n) = prod(k=1, n, 3*k-2);

%o a(n) = a007559(n)*sum(k=0, n, k/a007559(k));

%Y Cf. A007559, A368792.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Jan 05 2024