A083294 a(n) = (4 + (-9)^n)/5.

1, -1, 17, -145, 1313, -11809, 106289, -956593, 8609345, -77484097, 697356881, -6276211921, 56485907297, -508373165665, 4575358490993, -41178226418929, 370604037770369, -3335436339933313, 30018927059399825, -270170343534598417, 2431533091811385761

Offset: 0

Author

Paul Barry, Apr 24 2003

Keywords

• easy
• sign

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..300
• Index entries for linear recurrences with constant coefficients, signature (-8,9).

Crossrefs

Cf. A083295.

Programs

Magma

[(4+(-9)^n)/5: n in [0..30]]; // Vincenzo Librandi, Jun 08 2011

Mathematica

(4+(-9)^Range[0,20])/5 (* or *) LinearRecurrence[{-8,9},{1,-1},30] (* Harvey P. Dale, Sep 25 2021 *)

Formula

a(n) = (4 + (-9)^n)/5.

G.f.: (1+7*x)/((1-x)*(1+9*x)).

E.g.f.: (4*exp(x) + exp(-9*x))/5.