A005877 Theta series of cubic lattice with respect to square. (Formerly M3322)

4, 8, 8, 16, 12, 8, 24, 16, 16, 24, 16, 16, 28, 32, 8, 32, 32, 16, 40, 16, 16, 40, 40, 32, 36, 16, 24, 48, 32, 24, 40, 48, 16, 56, 32, 16, 64, 40, 32, 32, 36, 40, 48, 48, 32, 48, 48, 16, 80, 40, 24, 80

Offset

0,1

References

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 107.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

G. Nebe and N. J. A. Sloane, Home page for this lattice

Formula

a(n) = 4*A045828(n).

Mathematica

terms = 52; QP = QPochhammer; s = 4*(QP[q^2]^3*QP[q^4]^2)/QP[q]^2 + O[q]^terms; CoefficientList[s, q] (* Jean-François Alcover, Jul 05 2017 *)

Crossrefs

Cf. A045828.

Sequence in context: A273572 A273779 A114027 * A144174 A256816 A098354

Adjacent sequences: A005874 A005875 A005876 * A005878 A005879 A005880

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved