|
|
A014116
|
|
Order of automorphism group of Barnes-Wall lattice in dimension 2^n.
|
|
4
|
|
|
|
OFFSET
|
0,1
|
|
REFERENCES
|
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 129.
|
|
LINKS
|
|
|
MAPLE
|
2^(n^2+n+1) * (2^n - 1) * product('2^(2*i)-1', 'i'=1..n-1); # except for n=3.
|
|
PROG
|
(Python)
from math import prod
def A014116(n): return 2+696729598*(n//3) if n == 0 or n == 3 else ((1<<n)-1)*prod((1<<i)-1 for i in range(2, 2*n-1, 2)) << n*(n+1)+1 # Chai Wah Wu, Jun 20 2022
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|