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A035756
Coordination sequence for C_19 lattice.
1
1, 722, 87362, 4298066, 116323586, 2029779538, 25216532290, 238745924050, 1810015572994, 11406058224594, 61497762026306, 290259969857618, 1221518092836098, 4652599114237778, 16237772840882498, 52462123239704786, 158268201857667074, 449093392401112274, 1206082191029270850
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))^19.
CROSSREFS
Sequence in context: A133531 A206006 A231485 * A107552 A232261 A248484
KEYWORD
nonn,easy
AUTHOR
Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
EXTENSIONS
Recomputed by N. J. A. Sloane, Nov 25 1998
STATUS
approved