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A035854
Coordination sequence for A_28 lattice.
0
1, 812, 165242, 15055292, 780951962, 26359518332, 630816932522, 11367003681452, 161269749071102, 1864649147486972, 18058470057117602, 149786240635178252, 1083811462665042482, 6947150732631302732
OFFSET
0,2
LINKS
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
KEYWORD
nonn,easy
AUTHOR
Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
STATUS
approved