OFFSET
0,2
REFERENCES
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 105.
MATHEMATICA
s = (EllipticTheta[2, 0, q]^4 + EllipticTheta[3, 0, q]^4)/QPochhammer[q]^48 + O[q]^20; CoefficientList[s, q] (* Jean-François Alcover, Dec 03 2015 *)
PROG
(PARI) {a(n)=local(A); if(n<0, 0, A=x*O(x^n); polcoeff( sum(k=1, n, 24*sumdiv(k, d, d%2*d)*x^k, 1+A)/eta(x+A)^48, n))} /* Michael Somos, Feb 15 2006 */
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved