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A035845
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Coordination sequence for A_19 lattice.
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0
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1, 380, 36290, 1564460, 38906870, 640622012, 7634582090, 70098276620, 519252051080, 3214138597460, 17088309885542, 79759293448100, 332648955112250, 1257743358034100, 4363052456797550, 14025412751733092
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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 (19, -171, 969, -3876, 11628, -27132, 50388, -75582, 92378, -92378, 75582, -50388, 27132, -11628, 3876, -969, 171, -19, 1).
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FORMULA
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Sum_{d=1..19} C(20, d)*C(m/2-1, d-1)*C(19-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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