A151760 - OEIS

%I #8 Feb 02 2021 16:47:20

%S 0,0,0,0,1,4,6,8,13,12,10,16,18,16,20,24,13,12,18,16,22,24,28,24,18,

%T 16,28,24,20,24,24,0,13,12,18,16,30,24,28,24,22,24,36,24,28,24,24,0,

%U 18,16,28,24,28,24,24,0,20,24,24,0,24,0,0,0,13,12,18,16,30,24,28,24,30,24,36

%N G.f.: Theta^4, where Theta = Sum_{k>=0} x^(2^k).

%C Number of ways to write n as an ordered sum of 4 powers of 2. - _Ilya Gutkovskiy_, Feb 02 2021

%H Robert Israel, <a href="/A151760/b151760.txt">Table of n, a(n) for n = 0..10000</a>

%p N:= 10: # for a(0) .. a(2^N)

%p g:= add(x^(2^i),i=0..N)^4:

%p S:= series(g,x,2^N+1):

%p seq(coeff(S,x,j),j=0..2^N); # _Robert Israel_, Mar 27 2020

%Y Cf. A151758.

%K nonn

%O 0,6

%A _N. J. A. Sloane_, Jun 22 2009