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A035854
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Coordination sequence for A_28 lattice.
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0
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1, 812, 165242, 15055292, 780951962, 26359518332, 630816932522, 11367003681452, 161269749071102, 1864649147486972, 18058470057117602, 149786240635178252, 1083811462665042482, 6947150732631302732
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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 (28, -378, 3276, -20475, 98280, -376740, 1184040, -3108105, 6906900, -13123110, 21474180, -30421755, 37442160, -40116600, 37442160, -30421755, 21474180, -13123110, 6906900, -3108105, 1184040, -376740, 98280, -20475, 3276, -378, 28, -1).
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FORMULA
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Sum_{d=1..28} C(29, d)*C(m/2-1, d-1)*C(28-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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