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Search: id:A008397
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| A008397 |
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Coordination sequence for E_7 lattice. |
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+0
3
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| 1, 126, 2898, 25886, 133506, 490014, 1433810, 3573054, 7902594, 15942206, 29896146, 52834014, 88892930, 143501022, 223622226, 338022398, 497556738, 715478526, 1007769170, 1393489566
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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.
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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) = 148/5*n^6-12/5*n^5+52*n^4+12*n^3+212/5*n^2-48/5*n+2.
Bacher et al. give a g.f.
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MAPLE
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148/5*n^6-12/5*n^5+52*n^4+12*n^3+212/5*n^2-48/5*n+2;
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CROSSREFS
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Sequence in context: A109146 A133499 A113857 this_sequence A086024 A036403 A140902
Adjacent sequences: A008394 A008395 A008396 this_sequence A008398 A008399 A008400
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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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