A035858 Coordination sequence for A_32 lattice.

1, 1056, 279312, 33020768, 2216449224, 96447982752, 2962111270448, 68139802316256, 1226979622925364, 17893889175680672, 217162303201118352, 2242202047912186080, 20060152971318789560, 157926267134053719840

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 (32, -496, 4960, -35960, 201376, -906192, 3365856, -10518300, 28048800, -64512240, 129024480, -225792840, 347373600, -471435600, 565722720, -601080390, 565722720, -471435600, 347373600, -225792840, 129024480, -64512240, 28048800, -10518300, 3365856, -906192, 201376, -35960, 4960, -496, 32, -1).

Formula

Sum_{d=1..32} C(33, d)*C(m/2-1, d-1)*C(32-d+m/2, m/2), where norm m is always even.

Crossrefs

Sequence in context: A023072 A168627 A223294 * A120215 A351770 A202611

Adjacent sequences: A035855 A035856 A035857 * A035859 A035860 A035861

Keyword

nonn,easy

Author

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

Status

approved