This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A110204 #3 Mar 30 2012 18:36:49
%S A110204 0,0,0,225,3224,29274,215900,1412275,8541876,48876212,268288008,
%T A110204 1425694725,7381073920,37399844174,186110137668,911952794935,
%U A110204 4409472232060,21073909951080,99688911645264,467292120940425
%N A110204 a(n) = sum of squares of numbers < 2^n having exactly 4 ones in their binary representation.
%C A110204 Equals column 4 of triangle A110200.
%F A110204 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 A110204 (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 A110204 Cf. A110200 (triangle), A110201 (central terms), A002450 (column 1), A110202 (column 2), A110203 (column 3).
%K A110204 nonn
%O A110204 1,4
%A A110204 _Paul D. Hanna_, Jul 16 2005