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Sum of ninth powers of coefficients in full expansion of (z_1+z_2+...+z_n)^n.
2

%I #6 Jan 27 2023 20:55:04

%S 1,1,514,10195797,2703788516356,5361940142039062505,

%T 55063667396158825603112136,2272169230481993564658922073502463,

%U 312894608313254360747865383525129561090056,124773193097402414339622625011223384066643153613969

%N Sum of ninth powers of coefficients in full expansion of (z_1+z_2+...+z_n)^n.

%H Alois P. Heinz, <a href="/A246244/b246244.txt">Table of n, a(n) for n = 0..75</a>

%F a(n) = [x^n] (n!)^9 * (Sum_{j=0..n} x^j/(j!)^9)^n.

%p b:= proc(n, i) option remember; `if`(n=0 or i=1, 1,

%p add(b(n-j, i-1)*binomial(n, j)^9, j=0..n))

%p end:

%p a:= n-> b(n$2):

%p seq(a(n), n=0..15);

%Y Column k=9 of A245397.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Aug 19 2014