A321949 Column k=4 of triangle A257673.

1, 12, 78, 376, 1509, 5340, 17234, 51796, 147054, 398388, 1037560, 2612520, 6387965, 15221412, 35446980, 80865304, 181076216, 398660292, 864186408, 1846759404, 3894731430, 8113669352, 16710519860, 34049851236, 68687627812, 137257430140, 271842916654

Offset

4,2

Links

Alois P. Heinz, Table of n, a(n) for n = 4..5000

Formula

G.f.: (-1 + Product_{k>=1} 1 / (1 - x^k)^k)^4. - Ilya Gutkovskiy, Jan 30 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))(4):
seq(a(n), n=4..35);

Crossrefs

Column k=4 of A257673.

Sequence in context: A341225 A124863 A022577 * A227707 A189493 A199492

Adjacent sequences: A321946 A321947 A321948 * A321950 A321951 A321952

Keyword

nonn

Author

Alois P. Heinz, Nov 22 2018

Status

approved