A035856 Coordination sequence for A_30 lattice.

1, 930, 216690, 22583810, 1338036570, 51479517042, 1400792169890, 28618505434770, 458896797950430, 5976672906978410, 64971574193515962, 602758415976923850, 4860664625733355250, 34599738140887685850

Offset

0,2

Links

Table of n, a(n) for n=0..13.

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 (30, -435, 4060, -27405, 142506, -593775, 2035800, -5852925, 14307150, -30045015, 54627300, -86493225, 119759850, -145422675, 155117520, -145422675, 119759850, -86493225, 54627300, -30045015, 14307150, -5852925, 2035800, -593775, 142506, -27405, 4060, -435, 30, -1).

Formula

Sum_{d=1..30} C(31, d)*C(m/2-1, d-1)*C(30-d+m/2, m/2), where norm m is always even.

Crossrefs

Sequence in context: A158679 A250384 A209810 * A093231 A252530 A105213

Adjacent sequences: A035853 A035854 A035855 * A035857 A035858 A035859

Keyword

nonn,easy

Author

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

Status

approved