A168616 a(n) = 2^n - 5.

-4, -3, -1, 3, 11, 27, 59, 123, 251, 507, 1019, 2043, 4091, 8187, 16379, 32763, 65531, 131067, 262139, 524283, 1048571, 2097147, 4194299, 8388603, 16777211, 33554427, 67108859, 134217723, 268435451, 536870907, 1073741819, 2147483643

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature(3,-2).

Formula

a(n) = 2*a(n-1) + 5.

G.f. (9*x - 4)/((x-1)*(2*x-1)). - R. J. Mathar, Feb 22 2012

a(n) = 3*a(n-1) - 2*a(n-2). - Vincenzo Librandi, Sep 19 2013

E.g.f.: exp(2*x) - 5*exp(x). - G. C. Greubel, Jul 27 2016

Mathematica

Table[2^n-5, {n, 0, 5!}] (* Vladimir Joseph Stephan Orlovsky, Nov 22 2010 *)
CoefficientList[Series[(9 x - 4)/((x - 1) (2 x - 1)), {x, 0, 60}], x] (* Vincenzo Librandi, Sep 19 2013 *)
LinearRecurrence[{3, -2}, {-4, -3}, 40] (* Harvey P. Dale, Oct 15 2014 *)

Prog

(Magma) [2^n-5: n in [0..40]]; // Vincenzo Librandi, Sep 19 2013
(PARI) a(n)=2^n-5 \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

Sequence in context: A006467 A119505 A201518 * A375754 A342813 A296218

Adjacent sequences: A168613 A168614 A168615 * A168617 A168618 A168619

Keyword

sign,easy

Author

Vincenzo Librandi, Dec 01 2009

Extensions

Formula and examples edited to use correct offset by Jon E. Schoenfield, Jun 19 2010

Status

approved