A035852 Coordination sequence for A_26 lattice.

1, 702, 123552, 9746802, 438575202, 12873059082, 268708978512, 4237937201862, 52823066222862, 538709704223262, 4620645082106352, 34084184942296242, 220231986648034842, 1265712901796074842, 6554224549952044992

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 (26, -325, 2600, -14950, 65780, -230230, 657800, -1562275, 3124550, -5311735, 7726160, -9657700, 10400600, -9657700, 7726160, -5311735, 3124550, -1562275, 657800, -230230, 65780, -14950, 2600, -325, 26, -1).

Formula

Sum_{d=1..26} C(27, d)*C(m/2-1, d-1)*C(26-d+m/2, m/2), where norm m is always even.

Crossrefs

Sequence in context: A304766 A316510 A317464 * A214486 A045146 A083735

Adjacent sequences: A035849 A035850 A035851 * A035853 A035854 A035855

Keyword

nonn,easy

Author

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

Status

approved