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A035851
Coordination sequence for A_25 lattice.
0
1, 650, 105950, 7746050, 323371100, 8818775030, 171332460650, 2520031983950, 29356499303300, 280442899885850, 2258408187518990, 15677116400829650, 95542687574917700, 519065738821138550, 2546320423186207850
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 (25, -300, 2300, -12650, 53130, -177100, 480700, -1081575, 2042975, -3268760, 4457400, -5200300, 5200300, -4457400, 3268760, -2042975, 1081575, -480700, 177100, -53130, 12650, -2300, 300, -25, 1).
FORMULA
Sum_{d=1..25} C(26, d)*C(m/2-1, d-1)*C(25-d+m/2, m/2), where norm m is always even.
CROSSREFS
Sequence in context: A158639 A162025 A251861 * A229797 A110836 A252388
KEYWORD
nonn,easy
AUTHOR
Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
STATUS
approved