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 A008393 Coordination sequence for A_9 lattice. 2
 1, 90, 2070, 22530, 151560, 731502, 2777370, 8809110, 24314490, 60110030, 135916002, 285510150, 563873400, 1056789450, 1893408750, 3262336002, 5431848930, 8774904690, 13799638910, 21186110970, 31830097752, 46894786710 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS T. D. Noe, Table of n, a(n) for n = 0..1000 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 (9,-36,84,-126,126,-84,36,-9,1). FORMULA a(n) = 2 + 11*n^2*(221*n^6 + 2730*n^4 + 7917*n^2 + 5260)/2016, a(0) = 1. G.f.: (1+x)*(1 + 80*x + 1216*x^2 + 5840*x^3 + 10036*x^4 + 5840*x^5 + 1216*x^6 + 80*x^7 + x^8)/(1-x)^9. - Colin Barker, Sep 26 2012 MAPLE 1, seq(2 +11*n^2*(221*n^6 +2730*n^4 +7917*n^2 +5260)/2016, n=1..40); MATHEMATICA Table[11*n^2*(221*n^6 +2730*n^4 +7917*n^2 +5260)/2016 +2 -Boole[n==0], {n, 0, 40}] (* G. C. Greubel, May 27 2023 *) PROG (Magma) [1] cat [2 +11*n^2*(221*n^6 +2730*n^4 +7917*n^2 +5260)/2016: n in [1..40]]; // G. C. Greubel, May 27 2023 (SageMath) [11*n^2*(221*n^6 +2730*n^4 +7917*n^2 +5260)//2016 +2 -int(n==0) for n in range(41)] # G. C. Greubel, May 27 2023 CROSSREFS Row 9 of A103881. Sequence in context: A240259 A065951 A257040 * A055603 A210090 A109124 Adjacent sequences: A008390 A008391 A008392 * A008394 A008395 A008396 KEYWORD nonn,easy AUTHOR N. J. A. Sloane and J. H. Conway STATUS approved

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Last modified November 30 03:37 EST 2023. Contains 367452 sequences. (Running on oeis4.)