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Search: id:A008399
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| A008399 |
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Coordination sequence for E_6 lattice. |
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+0
2
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| 1, 72, 1062, 6696, 26316, 77688, 189810, 405720, 785304, 1408104, 2376126, 3816648, 5885028, 8767512, 12684042, 17891064, 24684336, 33401736, 44426070, 58187880, 75168252, 95901624, 120978594
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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R. Bacher, P. de la Harpe and B. Venkov, Series de croissance et series d'Ehrhart associees aux reseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.
M. O'Keeffe, Coordination sequences for lattices, Zeit. f. Krist., 210 (1995), 905-908.
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..1000
J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (Abstract, pdf, ps).
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FORMULA
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a(n) = 117/5*n^5+36*n^3+63/5*n.
Bacher et al. give a g.f.
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MAPLE
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117/5*n^5+36*n^3+63/5*n;
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CROSSREFS
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Cf. A019557, A019558, A008397, A008340.
Sequence in context: A113855 A082949 A019562 this_sequence A022148 A064567 A128800
Adjacent sequences: A008396 A008397 A008398 this_sequence A008400 A008401 A008402
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com) and J. H. Conway (conway(AT)math.princeton.edu)
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