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A035844
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Coordination sequence for A_18 lattice.
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0
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1, 342, 29412, 1143762, 25727292, 384468534, 4175000796, 35078339106, 238815143406, 1364497268946, 6724224543708, 29206656395910, 113779617228060, 403237594259010, 1315394383751460, 3988232552194662
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OFFSET
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0,2
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REFERENCES
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R. Bacher, P. de la Harpe and B. Venkov, Series de croissance et series d'Ehrhart associees aux reseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.
J. Serra-Sagrista, Enumeration of lattice points in l_1 norm, Information Processing Letters, 76, no. 1-2 (2000), 39-44.
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LINKS
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Table of n, a(n) for n=0..15.
J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (Abstract, pdf, ps).
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FORMULA
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Sum_{d=1}^18 C(19, d) C(m/2-1, d-1) C(18-d+m/2, m/2), where norm m is always even
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CROSSREFS
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Sequence in context: A043419 A158595 A023909 * A028681 A005072 A112821
Adjacent sequences: A035841 A035842 A035843 * A035845 A035846 A035847
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KEYWORD
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nonn,easy
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AUTHOR
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Serra-Sagrista, Joan; jserra(AT)ccd.uab.es
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STATUS
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approved
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