A022975 a(n) = 19 - n.

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

Offset: 0

Author

N. J. A. Sloane

Keywords

• sign

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Tanya Khovanova, Recursive Sequences.
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Cf. A022958 - A022995.

Programs

Magma

[19-n: n in [0..70]]; // Vincenzo Librandi, Jun 18 2016

Mathematica

CoefficientList[Series[(-20 x + 19) /(x - 1)^2, {x, 0, 100}], x] (* Vincenzo Librandi, Jun 18 2016 *)
19-Range[0,80] (* Harvey P. Dale, Aug 23 2017 *)

Formula

From Chai Wah Wu, Jun 17 2016: (Start)

a(n) = 2*a(n-1) - a(n-2) for n > 1.

G.f.: (-20*x + 19)/(x - 1)^2. (End)