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 A374535 #12 Jul 11 2024 08:38:15
%S A374535 0,1,7,19,31,61,133,189,213,330,510,642,786,968,1304,1664,1712,2018,
%T A374535 2720,3100,3460,4132,4924,5476,5764,6539,7631,8711,9383,10253,12413,
%U A374535 13405,13501,15085,16921,18601,20005,21411,23691,25875,26595,28317,32349,34241,35825,39335,42647,44903
%N A374535 Expansion of (x/(8 * (1-x))) * d/dx(theta_3(x)^4).
%F A374535 a(n) = 1/8 * Sum_{i,j,k,l in Z and i^2 + j^2 + k^2 + l^2 <= n} i^2 + j^2 + k^2 + l^2.
%F A374535 G.f.: (1/(1-x)) * Sum_{k>=1} k^2 * x^k / (1+(-x)^k)^2.
%o A374535 (PARI) my(N=50, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, k^2*x^k/(1+(-x)^k)^2)/(1-x)))
%Y A374535 Partial sums of A185152.
%Y A374535 Cf. A014203, A374534.
%K A374535 nonn
%O A374535 0,3
%A A374535 _Seiichi Manyama_, Jul 11 2024