A140683 a(n) = 3*(-1)^(n+1)*2^n - 1.

-4, 5, -13, 23, -49, 95, -193, 383, -769, 1535, -3073, 6143, -12289, 24575, -49153, 98303, -196609, 393215, -786433, 1572863, -3145729, 6291455, -12582913, 25165823, -50331649, 100663295, -201326593, 402653183, -805306369, 1610612735, -3221225473

Offset

0,1

Comments

Alternated reading of negative of A140660 and A140529.

The binomial transform yields -4 followed by the negative of A140657.

The inverse binomial transform yields essentially a signed version of A000244. - R. J. Mathar, Aug 02 2008

Links

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

Index entries for linear recurrences with constant coefficients, signature (-1, 2).

Formula

a(2n) = -A140660(n). a(2n+1) = A140529(n).

a(n+1) - a(n) = (-1)^n*A005010(n). a(2n) + a(2n+1) = A096045(n).

a(n) = A140590(n+1) - 2*A140590(n).

O.g.f: (4-x)/((x-1)(2x+1)). - R. J. Mathar, Aug 02 2008

a(n) = -a(n-1) + 2*a(n-2); a(0)=-4, a(1)=5. - Harvey P. Dale, May 26 2011

Mathematica

Table[3(-1)^(n+1)2^n-1, {n, 0, 40}] (* or *) LinearRecurrence[{-1, 2}, {-4, 5}, 40] (* Harvey P. Dale, May 26 2011 *)

Prog

(Magma) [3*(-1)^(n+1)*2^n-1: n in [0..40]]; // Vincenzo Librandi, Aug 08 2011

Crossrefs

Sequence in context: A005672 A147001 A247325 * A304599 A071341 A272898

Adjacent sequences: A140680 A140681 A140682 * A140684 A140685 A140686

Keyword

sign

Author

Paul Curtz, Jul 11 2008

Extensions

Edited and extended by R. J. Mathar, Aug 02 2008

Status

approved