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A321954 Column k=9 of triangle A257673.

%I A321954 #10 Jan 31 2021 08:11:10
%S A321954 1,27,378,3681,28134,180198,1007370,5051790,23173047,98644395,
%T A321954 394006761,1489460724,5365964511,18526724685,61587671283,197885754837,
%U A321954 616568620176,1868127089697,5517376711191,15917134652829,44935916034951,124340811582540,337706753653476
%N A321954 Column k=9 of triangle A257673.
%H A321954 Alois P. Heinz, <a href="/A321954/b321954.txt">Table of n, a(n) for n = 9..5000</a>
%F A321954 G.f.: (-1 + Product_{k>=1} 1 / (1 - x^k)^k)^9. - _Ilya Gutkovskiy_, Jan 31 2021
%p A321954 b:= proc(n, k) option remember; `if`(n=0, 1, k*add(
%p A321954       b(n-j, k)*numtheory[sigma][2](j), j=1..n)/n)
%p A321954     end:
%p A321954 a:= n-> (k-> add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k))(9):
%p A321954 seq(a(n), n=9..35);
%Y A321954 Column k=9 of A257673.
%K A321954 nonn
%O A321954 9,2
%A A321954 _Alois P. Heinz_, Nov 22 2018