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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.)