OFFSET
0,4
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
R. Bacher and B. B. Venkov, Réseaux entiers unimodulaires sans racine en dimension 27 et 28, in Réseaux euclidiens, designs sphériques et formes modulaires, pp. 212-267, Enseignement Math., Geneva, 2001.
J. H. Conway and N. J. A. Sloane, Sphere Packings, Lattices and Groups, Springer-Verlag, Preface to 3rd ed.
MAPLE
MATHEMATICA
terms = 18; QP = QPochhammer; th3 = EllipticTheta[3, 0, q]; delta8 = q*(QP[q]*(QP[q^4]/QP[q^2]))^8; s = th3^27 - 54*th3^19*delta8 + 216*th3^11*delta8^2 - 1024*th3^3*delta8^3 + O[q]^terms; CoefficientList[s, q] (* Jean-François Alcover, Jul 06 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved