cp's OEIS Frontend

A341226 Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^7.

%I A341226 #8 Feb 07 2021 11:47:02
%S A341226 1,14,105,567,2478,9317,31269,95965,273896,735966,1879059,4591342,
%T A341226 10797290,24549924,54171729,116368308,243991034,500446135,1006039762,
%U A341226 1985480063,3852429483,7358212272,13850448185,25718189483,47150564517,85417834621,153015826880
%N A341226 Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^7.
%H A341226 Alois P. Heinz, <a href="/A341226/b341226.txt">Table of n, a(n) for n = 7..10000</a>
%p A341226 b:= proc(n, k) option remember; `if`(k<2, `if`(n=0, 1-k, combinat[
%p A341226       numbpart](n)), (q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2)))
%p A341226     end:
%p A341226 a:= n-> b(n, 7):
%p A341226 seq(a(n), n=7..33);  # _Alois P. Heinz_, Feb 07 2021
%t A341226 nmax = 33; CoefficientList[Series[(-1 + Product[1/(1 - x^k), {k, 1, nmax}])^7, {x, 0, nmax}], x] // Drop[#, 7] &
%Y A341226 Column k=7 of A060642.
%Y A341226 Cf. A000041, A023006, A048574, A327385, A341221, A341222, A341223, A341225, A341227, A341228.
%K A341226 nonn
%O A341226 7,2
%A A341226 _Ilya Gutkovskiy_, Feb 07 2021