A035855 Coordination sequence for A_29 lattice.

1, 870, 189660, 18502290, 1026829680, 37041354030, 946156012020, 18170467948410, 274296114962940, 3368607034611630, 34588475083615740, 303610009666655370, 2320524189173327760, 15683018934278391990

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 (29, -406, 3654, -23751, 118755, -475020, 1560780, -4292145, 10015005, -20030010, 34597290, -51895935, 67863915, -77558760, 77558760, -67863915, 51895935, -34597290, 20030010, -10015005, 4292145, -1560780, 475020, -118755, 23751, -3654, 406, -29, 1).

Formula

Sum_{d=1..29} C(30, d)*C(m/2-1, d-1)*C(29-d+m/2, m/2), where norm m is always even.

Crossrefs

Sequence in context: A158669 A206172 A205426 * A317806 A031783 A253167

Adjacent sequences: A035852 A035853 A035854 * A035856 A035857 A035858

Keyword

nonn,easy

Author

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

Status

approved