A368791 a(n) = A008544(n) * Sum_{k=0..n} 1/A008544(k).

1, 3, 16, 129, 1420, 19881, 337978, 6759561, 155469904, 4042217505, 117224307646, 3751177844673, 131291224563556, 4989066533415129, 204551727870020290, 9000276026280892761, 423012973235201959768, 21150648661760097988401, 1120984379073285193385254

Offset

0,2

Links

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

Formula

a(n) = (3*n-1) * a(n-1) + 1.

Prog

(PARI) a008544(n) = prod(k=1, n, 3*k-1);
a(n) = a008544(n)*sum(k=0, n, 1/a008544(k));

Crossrefs

Row sums of A112333.

Cf. A008544, A368790.

Sequence in context: A289145 A340341 A362661 * A135752 A218827 A120021

Adjacent sequences: A368788 A368789 A368790 * A368792 A368793 A368794

Keyword

nonn,easy

Author

Seiichi Manyama, Jan 05 2024

Status

approved