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 A117726 #6 Dec 18 2012 10:38:24
%S A117726 2,4,4,4,8,8,4,8,10,8,12,8,8,16,8,8,16,12,12,16,16,8,12,16,10,24,16,8,
%T A117726 24,16,12,16,16,16,24,20,8,24,16,16,32,16,12,24,24,16,20,16,18,28,24,
%U A117726 16,24,32,16,32,16,8,36,16,24,32,20,16,32,32,12,32,32,16,28,24,16,40,28,24
%N A117726 Moreno and Wagstaff's arithmetical function T(n).
%C A117726 Also 4 times Kronecker's function F(n).
%C A117726 F(n) is the number of odd classes of binary quadratic forms ax^2+2bxy+cy^2 of discriminant b^2-ac = -n, where classes of the shape a(x^2+y^2) are counted as 1/2 and "odd" means that at least one of a and c is odd.
%D A117726 L. Kronecker, Crelle, Vol. LVII (1860), p. 248; Werke, Vol. IV, p. 188.
%D A117726 C. J. Moreno and S. S. Wagstaff, Jr., Sums of Squares of Integers, Chapman and Hall, 2006, p. 43.
%D A117726 H. J. S. Smith, Report on the Theory of Numbers, reprinted in Vol. 1 of his Collected Math. Papers, Chelsea, NY, 1979, see pp. 323 (definition of F), 338 (g.f.).
%F A117726 G.f. for F(n): Sum_{n >= 1} F(n) q^n = (q^(1/4) / Sum_{ m=-infinity, infinity } q^( (2*m+1)^2/4 )) * Sum{ n=-infinity, infinity } q^(n^2+n-1)/(1-q^(2*n-1))^2.
%p A117726 t10:=add( q^( (2*m+1)^2/4 ),m=-20..20); t1:=series(q^(1/4)/t10,q,100); t2:=add( q^(n^2+n-1)/(1-q^(2*n-1))^2,n=1..100): series(4*t1*t2,q,100);
%Y A117726 Cf. A117728, A005875.
%K A117726 nonn
%O A117726 1,1
%A A117726 _N. J. A. Sloane_, Apr 14 2006