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A321950 Column k=5 of triangle A257673.

%I A321950 #10 Jan 30 2021 22:50:23
%S A321950 1,15,120,695,3285,13473,49730,169115,538440,1623660,4677121,12955065,
%T A321950 34682730,90113220,227992870,563267203,1361992935,3229643480,
%U A321950 7522847555,17237982025,38905739524,86585024910,190193593830,412712252535,885382820550,1879084411753
%N A321950 Column k=5 of triangle A257673.
%H A321950 Alois P. Heinz, <a href="/A321950/b321950.txt">Table of n, a(n) for n = 5..5000</a>
%F A321950 G.f.: (-1 + Product_{k>=1} 1 / (1 - x^k)^k)^5. - _Ilya Gutkovskiy_, Jan 30 2021
%p A321950 b:= proc(n, k) option remember; `if`(n=0, 1, k*add(
%p A321950       b(n-j, k)*numtheory[sigma][2](j), j=1..n)/n)
%p A321950     end:
%p A321950 a:= n-> (k-> add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k))(5):
%p A321950 seq(a(n), n=5..35);
%Y A321950 Column k=5 of A257673.
%K A321950 nonn
%O A321950 5,2
%A A321950 _Alois P. Heinz_, Nov 22 2018