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 A169642 a(n) = A005408(n) * A022998(n). 2
 0, 3, 20, 21, 72, 55, 156, 105, 272, 171, 420, 253, 600, 351, 812, 465, 1056, 595, 1332, 741, 1640, 903, 1980, 1081, 2352, 1275, 2756, 1485, 3192, 1711, 3660, 1953, 4160, 2211, 4692, 2485, 5256, 2775, 5852, 3081, 6480, 3403, 7140, 3741, 7832, 4095, 8556 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Colin Barker, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (0,3,0,-3,0,1). FORMULA a(n)= +3*a(n-2) -3*a(n-4) +a(n-6). G.f.: -x*(3+20*x+12*x^2+12*x^3+x^4)/ ( (x-1)^3*(1+x)^3 ). - R. J. Mathar, Oct 09 2010 From Colin Barker, Dec 29 2016: (Start) a(n) = 4*n^2 + 2*n for n>0 and even. a(n) = 2*n^2 + n for n odd. (End) MATHEMATICA LinearRecurrence[{0, 3, 0, -3 , 0, 1}, {0 , 3, 20, 21, 72, 55}, 47] (* Georg Fischer, Feb 22 2019 *) PROG (PARI) concat(0, Vec(-x*(3+20*x+12*x^2+12*x^3+x^4)/ ((x-1)^3*(1+x)^3) + O(x^50))) \\ Colin Barker, Dec 29 2016 CROSSREFS Sequence in context: A212995 A081849 A333667 * A222482 A022129 A308721 Adjacent sequences:  A169639 A169640 A169641 * A169643 A169644 A169645 KEYWORD nonn,easy AUTHOR Paul Curtz, Apr 04 2010 EXTENSIONS Edited by N. J. A. Sloane, Apr 05 2010 More terms from R. J. Mathar, Oct 09 2010 STATUS approved

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Last modified May 24 21:08 EDT 2022. Contains 354043 sequences. (Running on oeis4.)