|
%I #3 Mar 30 2012 18:36:49
%S 0,0,0,225,3224,29274,215900,1412275,8541876,48876212,268288008,
%T 1425694725,7381073920,37399844174,186110137668,911952794935,
%U 4409472232060,21073909951080,99688911645264,467292120940425
%N a(n) = sum of squares of numbers < 2^n having exactly 4 ones in their binary representation.
%C Equals column 4 of triangle A110200.
%F G.f.: x^4*(225-2626*x+12500*x^2-30872*x^3+41536*x^4-28928*x^5+8192*x^6)/ ((1-x)^4*(1-2*x)^3*(1-4*x)^4).
%o (PARI) {a(n)=polcoeff(x^4*(225-2626*x+12500*x^2-30872*x^3+41536*x^4-28928*x^5+8192*x^6)/ ((1-x)^4*(1-2*x)^3*(1-4*x)^4+x*O(x^n)),n)}
%Y Cf. A110200 (triangle), A110201 (central terms), A002450 (column 1), A110202 (column 2), A110203 (column 3).
%K nonn
%O 1,4
%A _Paul D. Hanna_, Jul 16 2005
|
