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A008359
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Coordination sequence for D_7 lattice.
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2
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1, 84, 1498, 11620, 55650, 195972, 559258, 1371316, 2999682, 6003956, 11193882, 19695172, 33023074, 53163684, 82663002, 124723732, 183309826, 263258772, 370401626, 511690788, 695335522
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OFFSET
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0,2
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..1000
M. Baake and U. Grimm, Coordination sequences for root lattices and related graphs, arXiv:cond-mat/9706122 [cond-mat.stat-mech], 1997; Zeit. f. Kristallographie, 212 (1997), 253-256
R. Bacher, P. de la Harpe and B. Venkov, Séries de croissance et séries d'Ehrhart associées aux réseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.
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 (7,-21,35,-35,21,-7,1).
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FORMULA
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G.f.: (x+1)*(x^6 + 76*x^5 + 855*x^4 + 2008*x^3 + 855*x^2 + 76*x + 1)/(1-x)^7. [Colin Barker, Sep 26 2012; corrected by Georg Fischer, May 19 2019]
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MAPLE
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484/45*n^6+392/9*n^4+1246/45*n^2+2;
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CROSSREFS
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A row of array A103903.
Sequence in context: A277784 A105942 A219476 * A166847 A219938 A271670
Adjacent sequences: A008356 A008357 A008358 * A008360 A008361 A008362
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane and J. H. Conway
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STATUS
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approved
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