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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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LINKS
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J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).
Index entries for linear recurrences with constant coefficients, signature (18, -153, 816, -3060, 8568, -18564, 31824, -43758, 48620, -43758, 31824, -18564, 8568, -3060, 816, -153, 18, -1).
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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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KEYWORD
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nonn,easy
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AUTHOR
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Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
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STATUS
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approved
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