A035850 Coordination sequence for A_24 lattice.

1, 600, 90300, 6100200, 235597650, 5953712520, 107392877100, 1469778991800, 15969368635950, 142638039461400, 1076681464768860, 7023070170402600, 40317756506959050, 206818794600952200, 960154451013729900

Offset

0,2

Links

Table of n, a(n) for n=0..14.

R. Bacher, P. de la Harpe and B. Venkov, Séries de croissance et séries d'Ehrhart associées aux réseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).

Joan Serra-Sagrista, Enumeration of lattice points in l_1 norm, Inf. Proc. Lett. 76 (1-2) (2000) 39-44.

Index entries for linear recurrences with constant coefficients, signature (24, -276, 2024, -10626, 42504, -134596, 346104, -735471, 1307504, -1961256, 2496144, -2704156, 2496144, -1961256, 1307504, -735471, 346104, -134596, 42504, -10626, 2024, -276, 24, -1).

Formula

Sum_{d=1..24} C(25, d)*C(m/2-1, d-1)*C(24-d+m/2, m/2), where norm m is always even.

Crossrefs

Sequence in context: A048530 A223463 A023915 * A093260 A008689 A126835

Adjacent sequences: A035847 A035848 A035849 * A035851 A035852 A035853

Keyword

nonn,easy

Author

Joan Serra-Sagrista (jserra(AT)ccd.uab.es)

Status

approved