login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168589 a(n) = (2 - 3^n)*(-1)^n. 3
1, 1, -7, 25, -79, 241, -727, 2185, -6559, 19681, -59047, 177145, -531439, 1594321, -4782967, 14348905, -43046719, 129140161, -387420487, 1162261465, -3486784399, 10460353201, -31381059607, 94143178825, -282429536479 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

A signed version of A058481 preceded by 1.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (-4, -3).

FORMULA

a(n) = -4*a(n-1) - 3*a(n-2) for n > 1; a(0) = 1, a(1) = 1.

G.f.: (1 + 5*x)/((1+x)*(1+3*x)).

E.g.f.: 2*exp(-x) - exp(-3*x). - G. C. Greubel, Jul 26 2016

MATHEMATICA

Table[(2 - 3^n)*(-1)^n, {n, 0, 50}] (* G. C. Greubel, Jul 26 2016 *)

PROG

(MAGMA) [ (2-3^n)*(-1)^n: n in [0..25] ];

(PARI) a(n)=(2-3^n)*(-1)^n \\ Charles R Greathouse IV, Jul 26 2016

CROSSREFS

Cf. A058481 (3^n-2).

Sequence in context: A155281 A155254 A155295 * A058481 A220387 A155294

Adjacent sequences:  A168586 A168587 A168588 * A168590 A168591 A168592

KEYWORD

sign,easy

AUTHOR

Klaus Brockhaus, Nov 30 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 23:39 EDT 2018. Contains 316405 sequences. (Running on oeis4.)