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A035870
Coordination sequence for A_44 lattice.
0
1, 1980, 981090, 216711660, 27061623270, 2177841424572, 122794030719690, 5141202142881420, 166859335434401280, 4339352594947119860, 92842142609089290582, 1669788291963834188100, 25701287295018962756250
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 (44, -946, 13244, -135751, 1086008, -7059052, 38320568, -177232627, 708930508, -2481256778, 7669339132, -21090682613, 51915526432, -114955808528, 229911617056, -416714805914, 686353797976, -1029530696964, 1408831480056, -1761039350070, 2012616400080, -2104098963720, 2012616400080, -1761039350070, 1408831480056, -1029530696964, 686353797976, -416714805914, 229911617056, -114955808528, 51915526432, -21090682613, 7669339132, -2481256778, 708930508, -177232627, 38320568, -7059052, 1086008, -135751, 13244, -946, 44, -1).
FORMULA
Sum_{d=1..44} C(45, d)*C(m/2-1, d-1)*C(44-d+m/2, m/2), where norm m is always even.
CROSSREFS
Sequence in context: A289907 A125490 A237334 * A345517 A345770 A252693
KEYWORD
nonn,easy
AUTHOR
Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
STATUS
approved