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A035857
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Coordination sequence for A_31 lattice.
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0
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1, 992, 246512, 27390112, 1728939192, 70807488864, 2048715010256, 44450256810016, 755891034102316, 10424936982850656, 119820002520271088, 1173396885194646560, 9972151083876157960, 74688593871319112160
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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 (31, -465, 4495, -31465, 169911, -736281, 2629575, -7888725, 20160075, -44352165, 84672315, -141120525, 206253075, -265182525, 300540195, -300540195, 265182525, -206253075, 141120525, -84672315, 44352165, -20160075, 7888725, -2629575, 736281, -169911, 31465, -4495, 465, -31, 1).
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FORMULA
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Sum_{d=1..31} C(32, d)*C(m/2-1, d-1)*C(31-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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