login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A008665 Theta series of direct sum of 2 copies of b.c.c. lattice. 1
1, 0, 0, 16, 12, 0, 64, 96, 60, 0, 0, 240, 160, 0, 384, 416, 252, 0, 0, 720, 312, 0, 960, 1056, 544, 0, 0, 1312, 960, 0, 1664, 1920, 1020, 0, 0, 2496, 876, 0, 2880, 2720, 1560, 0, 0, 3696, 2400, 0, 4224, 4416 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 116.

LINKS

Table of n, a(n) for n=0..47.

Index entries for sequences related to b.c.c. lattice

FORMULA

G.f.: (theta_3(z)*theta_3(z)*theta_3(z)+theta_2(z)*theta_2(z)*theta_2(z))^2.

MATHEMATICA

terms = 48; t2 = EllipticTheta[2, 0, z]; t3 = EllipticTheta[3, 0, z]; s = Normal[(t3^3 + t2^3)^2 + O[z]^terms] /. z -> z^4 // Simplify[#, z > 0]&; CoefficientList[s, z][[1 ;; terms]] (* Jean-Fran├žois Alcover, Jul 06 2017 *)

CROSSREFS

Sequence in context: A225842 A298450 A028695 * A076823 A070551 A028493

Adjacent sequences:  A008662 A008663 A008664 * A008666 A008667 A008668

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 20 05:01 EDT 2019. Contains 324229 sequences. (Running on oeis4.)