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 A007589 Dodecahedral surface numbers: a(0)=0, a(1)=1, a(2)=20, thereafter 2*((3*n-7)^2 +21). (Formerly M5083) 1
 0, 1, 20, 50, 92, 170, 284, 434, 620, 842, 1100, 1394, 1724, 2090, 2492, 2930, 3404, 3914, 4460, 5042, 5660, 6314, 7004, 7730, 8492, 9290, 10124, 10994, 11900, 12842, 13820, 14834, 15884, 16970, 18092, 19250 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = Vertices + Edges*(n-2) + Faces*facenumber(n-3) = 20 + 30(n-2) + 12*A000326(n-3) - Mitch Harris, Oct 25 2006 MATHEMATICA Join[{0, 1, 20}, 2((3Range[3, 40]-7)^2+21)] (* Harvey P. Dale, Sep 24 2011 *) Join[{0, 1, 20}, CoefficientList[Series[2*(25-29*x+22*x^2)/(1-x)^3, {x, 0, 50}], x] ] (* Vincenzo Librandi, Jul 07 2012 *) PROG (MAGMA) I:=[0, 1, 20, 50, 92, 170]; [n le 6 select I[n] else 3*Self(n-1)-3*Self(n-2)+Self(n-3): n in [1..50]]; // Vincenzo Librandi, Jul 07 2012 CROSSREFS Sequence in context: A277553 A260093 A304832 * A182462 A231293 A227771 Adjacent sequences:  A007586 A007587 A007588 * A007590 A007591 A007592 KEYWORD nonn,easy AUTHOR EXTENSIONS Revised definition - N. J. A. Sloane, Sep 25 2011 STATUS approved

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Last modified October 15 17:12 EDT 2018. Contains 316237 sequences. (Running on oeis4.)