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A035768
Coordination sequence for C_31 lattice.
1
1, 1922, 616962, 79711106, 5573863426, 245955974018, 7532156369410, 170856126160770, 3010714725097474, 42741155411865474, 503090409749666306, 5025399107633316738, 43425584300428732418, 329863641871506905986, 2232693297068905613826, 13622726261084045211522
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.
FORMULA
a(n) = [x^(2n)] ((1+x)/(1-x))^31.
CROSSREFS
Sequence in context: A252148 A252141 A157448 * A107564 A135648 A363821
KEYWORD
nonn,easy
AUTHOR
Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
EXTENSIONS
Recomputed by N. J. A. Sloane, Nov 25 1998
STATUS
approved