login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A008688 Theta series of Niemeier lattice of type D_24. 15
1, 1104, 170064, 17051328, 396408912, 4634713440, 34410979008, 187471449984, 814973040720, 2975426026128, 9486423324000, 27053536131648, 70485827477184, 169930457503968, 384164030001024 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

LINKS

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

MATHEMATICA

(* Coefficients 11/9 and -2/9 were computed from the data. *)

terms = 15; E4[q_] := 1 + 240 Sum[DivisorSigma[3, n]*q^(2 n), {n, 1, terms}]; E6[q_] := 1 - 504 Sum[DivisorSigma[5, n]*q^(2 n), {n, 1, terms}]; s = 11/9 E4[q]^3 - 2/9 E6[q]^2 + O[q]^(3 terms); Partition[ CoefficientList[s, q], 2][[All, 1]][[1 ;; terms]] (* Jean-Fran├žois Alcover, Jul 06 2017 *)

CROSSREFS

Cf. A008689 - A008704.

Sequence in context: A233563 A127308 A022055 * A107519 A331641 A168629

Adjacent sequences:  A008685 A008686 A008687 * A008689 A008690 A008691

KEYWORD

nonn

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 August 6 11:55 EDT 2020. Contains 336246 sequences. (Running on oeis4.)