A122874 List of pairs n+7, 13-n, n >= 0.

7, 13, 8, 12, 9, 11, 10, 10, 11, 9, 12, 8, 13, 7, 14, 6, 15, 5, 16, 4, 17, 3, 18, 2, 19, 1, 20, 0, 21, -1, 22, -2, 23, -3, 24, -4, 25, -5, 26, -6, 27, -7, 28, -8, 29, -9, 30, -10, 31, -11, 32, -12, 33, -13, 34, -14, 35, -15, 36, -16, 37, -17, 38, -18, 39, -19, 40, -20, 41, -21, 42

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (-1,1,1).

Formula

a(n) = -a(n-1)+a(n-2)+a(n-3). G.f.: -(7+20*x+14*x^2)/((x-1)*(1+x)^2). [R. J. Mathar, Aug 07 2009]

Mathematica

CoefficientList[Series[-(7 + 20 x + 14 x^2)/((x - 1) (1 + x)^2), {x, 0, 100}], x] (* Vincenzo Librandi, May 25 2014 *)

Prog

(Magma) &cat[[n+7, 13-n]: n in [0..30]]; // Vincenzo Librandi, May 25 2014

Crossrefs

Sequence in context: A369717 A365346 A215990 * A066003 A115858 A114389

Adjacent sequences: A122871 A122872 A122873 * A122875 A122876 A122877

Keyword

sign,tabf,easy

Author

Stuart M. Ellerstein (ellerstein(AT)aol.com), Oct 23 2006

Extensions

Edited with better definition by Omar E. Pol and N. J. A. Sloane, Jan 02 2009

More terms from R. J. Mathar, Aug 07 2009

Status

approved