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A035866
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Coordination sequence for A_40 lattice.
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0
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1, 1640, 673220, 123273880, 12774087510, 854286594072, 40098332182820, 1400550765961960, 38011151426301640, 828828255977397080, 14911158035799862332, 226193352868905599400, 2945866488164585776650
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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 (40, -780, 9880, -91390, 658008, -3838380, 18643560, -76904685, 273438880, -847660528, 2311801440, -5586853480, 12033222880, -23206929840, 40225345056, -62852101650, 88732378800, -113380261800, 131282408400, -137846528820, 131282408400, -113380261800, 88732378800, -62852101650, 40225345056, -23206929840, 12033222880, -5586853480, 2311801440, -847660528, 273438880, -76904685, 18643560, -3838380, 658008, -91390, 9880, -780, 40, -1).
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FORMULA
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Sum_{d=1..40} C(41, d)*C(m/2-1, d-1)*C(40-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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