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A246242 Sum of seventh powers of coefficients in full expansion of (z_1+z_2+...+z_n)^n.

%I A246242 #4 Aug 19 2014 20:21:16
%S A246242 1,1,130,293061,5018329348,414999981562505,124389170238814179336,
%T A246242 110807909819808911886548575,253626563859350391170222920686088,
%U A246242 1334380576777390115212093953972864348177,14777734823564325121187478504310896072495827020
%N A246242 Sum of seventh powers of coefficients in full expansion of (z_1+z_2+...+z_n)^n.
%H A246242 Alois P. Heinz, <a href="/A246242/b246242.txt">Table of n, a(n) for n = 0..90</a>
%F A246242 a(n) = [x^n] (n!)^7 * (Sum_{j=0..n} x^j/(j!)^7)^n.
%p A246242 b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
%p A246242       add(b(n-j, i-1)*binomial(n, j)^6/j!, j=0..n)))
%p A246242     end:
%p A246242 a:= n-> n!*b(n$2):
%p A246242 seq(a(n), n=0..15);
%Y A246242 Column k=7 of A245397.
%K A246242 nonn
%O A246242 0,3
%A A246242 _Alois P. Heinz_, Aug 19 2014