A081630 2-(-3)^n.

1, 5, -7, 29, -79, 245, -727, 2189, -6559, 19685, -59047, 177149, -531439, 1594325, -4782967, 14348909, -43046719, 129140165, -387420487, 1162261469, -3486784399, 10460353205, -31381059607, 94143178829, -282429536479, 847288609445, -2541865828327, 7625597484989

Offset: 0

Author

Paul Barry, Mar 26 2003

Keywords

• easy
• sign

Comments

Binomial transform of A081629. Inverse binomial transform of A081631.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (-2,3).

Programs

Magma

[2-(-3)^n: n in [0..30]]; // Vincenzo Librandi Aug 09 2013

Mathematica

LinearRecurrence[{-2, 3}, {1, 5}, 30] (* Harvey P. Dale, Mar 25 2013 *)
CoefficientList[Series[(1 + 7 x) / ((1 - x) (1 + 3 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Aug 09 2013 *)

Formula

G.f.: (1+7*x)/((1-x)*(1+3*x)).

E.g.f. 2*exp(x)-exp(-3*x)