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 A026057 a(n) = n*(n^2+12*n-25)/6. 4
 0, -2, 1, 10, 26, 50, 83, 126, 180, 246, 325, 418, 526, 650, 791, 950, 1128, 1326, 1545, 1786, 2050, 2338, 2651, 2990, 3356, 3750, 4173, 4626, 5110, 5626, 6175, 6758, 7376, 8030, 8721, 9450, 10218, 11026, 11875, 12766, 13700, 14678, 15701, 16770, 17886, 19050 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS For n >= 4, this is dot_product(n,n-1,...2,1)*(4,5,...,n,1,2,3). LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA G.f.: x*(-2+9*x-6*x^2)/(1-x)^4. - Colin Barker, Sep 17 2012 MATHEMATICA CoefficientList[Series[x (- 2 + 9 x - 6 x^2)/(1 - x)^4, {x, 0, 60}], x] (* Vincenzo Librandi, Oct 17 2013 *) PROG (MAGMA) [n*(n^2+12*n-25)/6: n in [0..60]]; // Vincenzo Librandi, Oct 17 2013 (PARI) a(n)=n*(n^2+12*n-25)/6 \\ Charles R Greathouse IV, Oct 07 2015 CROSSREFS Cf. column 3 of triangle A094415. Sequence in context: A290597 A136205 A024433 * A309234 A071926 A133103 Adjacent sequences:  A026054 A026055 A026056 * A026058 A026059 A026060 KEYWORD sign,easy AUTHOR EXTENSIONS New definition from Ralf Stephan, Apr 30 2004 Edited by N. J. A. Sloane, Dec 13 2008 STATUS approved

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Last modified October 13 18:57 EDT 2019. Contains 327981 sequences. (Running on oeis4.)