A321954 Column k=9 of triangle A257673.

1, 27, 378, 3681, 28134, 180198, 1007370, 5051790, 23173047, 98644395, 394006761, 1489460724, 5365964511, 18526724685, 61587671283, 197885754837, 616568620176, 1868127089697, 5517376711191, 15917134652829, 44935916034951, 124340811582540, 337706753653476

Offset

9,2

Links

Alois P. Heinz, Table of n, a(n) for n = 9..5000

Formula

G.f.: (-1 + Product_{k>=1} 1 / (1 - x^k)^k)^9. - Ilya Gutkovskiy, Jan 31 2021

Maple

b:= proc(n, k) option remember; `if`(n=0, 1, k*add(
      b(n-j, k)*numtheory[sigma][2](j), j=1..n)/n)
    end:
a:= n-> (k-> add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k))(9):
seq(a(n), n=9..35);

Crossrefs

Column k=9 of A257673.

Sequence in context: A162726 A010979 A022591 * A000535 A251770 A033280

Adjacent sequences: A321951 A321952 A321953 * A321955 A321956 A321957

Keyword

nonn

Author

Alois P. Heinz, Nov 22 2018

Status

approved