|
Search: id:A008655
|
|
|
| A008655 |
|
Theta series of direct sum of 4 copies of hexagonal lattice. |
|
+0
1
|
|
| 1, 24, 216, 888, 1752, 3024, 7992, 8256, 14040, 24216, 27216, 31968, 64824, 52752, 74304, 111888, 112344, 117936, 217944, 164640, 220752, 305472, 287712, 292032, 519480, 378024, 474768, 654072
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.
|
|
REFERENCES
|
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 110.
J. McKay and A. Sebbar, Fuchsian groups, automorphic functions and Schwarzians, Math. Ann., 318 (2000), 255-275.
|
|
LINKS
|
G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2
|
|
FORMULA
|
Expansion of (theta_3(z)*theta_3(3z)+theta_2(z)*theta_2(3z))^4.
|
|
CROSSREFS
|
Sequence in context: A097321 A105946 A050222 this_sequence A133754 A104670 A138406
Adjacent sequences: A008652 A008653 A008654 this_sequence A008656 A008657 A008658
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com).
|
|
|
Search completed in 0.002 seconds
|
