A035854 - OEIS

A035854

Coordination sequence for A_28 lattice.

1, 812, 165242, 15055292, 780951962, 26359518332, 630816932522, 11367003681452, 161269749071102, 1864649147486972, 18058470057117602, 149786240635178252, 1083811462665042482, 6947150732631302732

(list; graph; refs; listen; history; text; internal format)

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 (28, -378, 3276, -20475, 98280, -376740, 1184040, -3108105, 6906900, -13123110, 21474180, -30421755, 37442160, -40116600, 37442160, -30421755, 21474180, -13123110, 6906900, -3108105, 1184040, -376740, 98280, -20475, 3276, -378, 28, -1).

FORMULA

Sum_{d=1..28} C(29, d)*C(m/2-1, d-1)*C(28-d+m/2, m/2), where norm m is always even.

CROSSREFS

Sequence in context: A045228 A252223 A158667 * A099116 A183820 A272606

Adjacent sequences: A035851 A035852 A035853 * A035855 A035856 A035857

KEYWORD

nonn,easy

AUTHOR

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

STATUS

approved

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