cp's OEIS Frontend

A319922 Number of ways of writing n as a sum of exactly 10 powers of 2.

%I A319922 #11 Oct 01 2018 18:16:45
%S A319922 0,0,0,0,0,0,0,0,0,0,1,1,1,2,2,2,3,4,4,5,6,5,6,6,7,8,9,8,10,9,10,11,
%T A319922 13,11,14,12,13,12,15,12,16,14,16,14,18,15,19,17,21,18,22,17,22,18,22,
%U A319922 19,25,19,24,20,25,21,28,21,27,21,26,19,27,20,26,19
%N A319922 Number of ways of writing n as a sum of exactly 10 powers of 2.
%H A319922 Alois P. Heinz, <a href="/A319922/b319922.txt">Table of n, a(n) for n = 0..65536</a>
%F A319922 a(n) = [x^n y^10] 1/Product_{j>=0} (1-y*x^(2^j)).
%p A319922 h:= proc(n) option remember; `if`(n<1, 0,
%p A319922       `if`(n=2^ilog2(n), n, h(n-1)))
%p A319922     end:
%p A319922 b:= proc(n, i, k) option remember; `if`(n=0, `if`(k=0, 1, 0), `if`(
%p A319922       k>n or i*k<n, 0, b(n, h(i-1), k)+b(n-i, h(min(n-i, i)), k-1)))
%p A319922     end:
%p A319922 a:= n-> b(n, h(n), 10):
%p A319922 seq(a(n), n=0..120);
%Y A319922 Column k=10 of A089052.
%Y A319922 Cf. A000079.
%K A319922 nonn,look
%O A319922 0,14
%A A319922 _Alois P. Heinz_, Oct 01 2018