The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A135446 a(n) = 3*a(n-1) - 3*a(n-2) + 2*a(n-3). 1
-1, -1, 3, 10, 19, 33, 62, 125, 255, 514, 1027, 2049, 4094, 8189, 16383, 32770, 65539, 131073, 262142, 524285, 1048575, 2097154, 4194307, 8388609, 16777214, 33554429, 67108863, 134217730, 268435459, 536870913, 1073741822 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Sequence identical to its third differences.
LINKS
FORMULA
a(n+1) - 2*a(n) = hexaperiodic 1, 5, 4, -1, -5, -4, A130815.
a(n) = 2^n - 2*cos((Pi*n)/3) - (4*sqrt(3)/3)*sin((Pi*n)/3). Or, a(n) = 2^n + [ -2; -3; -1; 2; 3; 1]. - Richard Choulet, Dec 31 2007
G.f.: (1+x)*(1-3*x) / ( (2*x-1)*(x^2-x+1) ). - R. J. Mathar, Nov 07 2015
MATHEMATICA
a = {-1, -1, 3}; Do[AppendTo[a, 3*a[[ -1]] - 3*a[[ -2]] + 2*a[[ -3]]], {40}]; a (* Stefan Steinerberger, Dec 22 2007 *)
LinearRecurrence[{3, -3, 2}, {-1, -1, 3}, 31] (* Ray Chandler, Sep 23 2015 *)
CROSSREFS
Sequence in context: A028878 A010896 A234940 * A160002 A294421 A027177
KEYWORD
sign,easy
AUTHOR
Paul Curtz, Dec 13 2007
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 21 08:56 EDT 2024. Contains 372733 sequences. (Running on oeis4.)