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 A008254 Coordination sequence T1 for feldspar. 1
 1, 4, 10, 20, 38, 58, 80, 112, 144, 180, 226, 270, 320, 380, 436, 500, 574, 642, 720, 808, 888, 980, 1082, 1174, 1280, 1396, 1500, 1620, 1750, 1866, 2000, 2144, 2272, 2420, 2578, 2718, 2880, 3052, 3204, 3380, 3566, 3730, 3920, 4120, 4296, 4500, 4714, 4902 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES Inorganic Crystal Structure Database: Collection Code 100182. LINKS Colin Barker, Table of n, a(n) for n = 0..1000 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. Sean A. Irvine, Generating Functions for Coordination Sequences of Zeolites, after Grosse-Kunstleve, Brunner, and Sloane Index entries for linear recurrences with constant coefficients, signature (1,0,2,-2,0,-1,1). FORMULA a(3*m) = 20*m^2, a(3*m+1) = 20*m^2+14*m+4, a(3*m+2) = 20*m^2+26*m+12 (m>0). G.f.: (1+x)*(1+2*x+4*x^2+4*x^3+8*x^4+3*x^6-4*x^7+2*x^8) / ((1-x)^3*(1+x+x^2)^2). - Colin Barker, Dec 22 2015 MATHEMATICA Table[SeriesCoefficient[(1 + x) (1 + 2 x + 4 x^2 + 4 x^3 + 8 x^4 + 3 x^6 - 4 x^7 + 2 x^8)/((1 - x)^3 (1 + x + x^2)^2), {x, 0, n}], {n, 0, 47}] (* Michael De Vlieger, Dec 22 2015 *) PROG (PARI) Vec((1+x)*(1+2*x+4*x^2+4*x^3+8*x^4+3*x^6-4*x^7+2*x^8)/((1-x)^3*(1+x+x^2)^2) + O(x^100)) \\ Colin Barker, Dec 22 2015 CROSSREFS Sequence in context: A188280 A295950 A038420 * A301178 A279262 A168673 Adjacent sequences: A008251 A008252 A008253 * A008255 A008256 A008257 KEYWORD nonn,easy AUTHOR Georg Thimm (mgeorg(AT)ntu.edu.sg) and Ralf W. Grosse-Kunstleve STATUS approved

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Last modified September 23 21:37 EDT 2023. Contains 365554 sequences. (Running on oeis4.)