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 A009945 Coordination sequence for NiAs(2), As position. 1
 1, 6, 18, 42, 74, 114, 162, 222, 290, 366, 450, 546, 650, 762, 882, 1014, 1154, 1302, 1458, 1626, 1802, 1986, 2178, 2382, 2594, 2814, 3042, 3282, 3530, 3786, 4050, 4326, 4610, 4902, 5202, 5514, 5834, 6162, 6498, 6846, 7202, 7566, 7938, 8322, 8714 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES Gmelin Handbook of Inorg. and Organomet. Chem., 8th Ed., 1994, TYPIX search code (194) hP4. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 R. W. Grosse-Kunstleve, Coordination Sequences and Encyclopedia of Integer Sequences R. W. Grosse-Kunstleve, G. O. Brunner and N. J. A. Sloane, Algebraic Description of Coordination Sequences and Exact Topological Densities for Zeolites, Acta Cryst., A52 (1996), pp. 879-889. Index entries for linear recurrences with constant coefficients, signature (2,-1,0,1,-2,1). FORMULA a(0)=1, a(4n)=2*((6n)^2+1), a(4n+2)=18*(2n+1)^2, a(2n+1)=6*(3n^2+3n+1). - Ralf Stephan, Mar 07 2004 G.f.: -(x^3+x^2+3*x+1)*(x^3+3*x^2+x+1) / ((x-1)^3*(x+1)*(x^2+1)). - Colin Barker, Aug 30 2013 MATHEMATICA CoefficientList[Series[-(x^3 + x^2 + 3 x + 1) (x^3 + 3 x^2 + x + 1)/((x - 1)^3 (x + 1) (x^2 + 1)), {x, 0, 50}], x] (* Vincenzo Librandi, Oct 15 2013 *) CROSSREFS Sequence in context: A074837 A286308 A015942 * A270683 A011930 A330844 Adjacent sequences:  A009942 A009943 A009944 * A009946 A009947 A009948 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified May 18 17:04 EDT 2021. Contains 343995 sequences. (Running on oeis4.)