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A035875
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Coordination sequence for A_49 lattice.
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0
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1, 2450, 1501850, 410171650, 63268601550, 6281159100090, 436163484794450, 22445862850491850, 893380572775009900, 28420188510300017550, 741763560322460452070, 16226209913927156169950, 302824866196247627529850
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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 (49, -1176, 18424, -211876, 1906884, -13983816, 85900584, -450978066, 2054455634, -8217822536, 29135916264, -92263734836, 262596783764, -675248872536, 1575580702584, -3348108992991, 6499270398159, -11554258485616, 18851684897584, -28277527346376, 39049918716424, -49699896548176, 58343356817424, -63205303218876, 63205303218876, -58343356817424, 49699896548176, -39049918716424, 28277527346376, -18851684897584, 11554258485616, -6499270398159, 3348108992991, -1575580702584, 675248872536, -262596783764, 92263734836, -29135916264, 8217822536, -2054455634, 450978066, -85900584, 13983816, -1906884, 211876, -18424, 1176, -49, 1).
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FORMULA
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Sum_{d=1..49} C(50, d)*C(m/2-1, d-1)*C(49-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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