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!)
A032124 "BIK" (reversible, indistinct, unlabeled) transform of 2,2,2,2... 1
2, 5, 12, 33, 90, 261, 756, 2241, 6642, 19845, 59292, 177633, 532170, 1595781, 4785156, 14353281, 43053282, 129153285, 387440172, 1162300833, 3486843450, 10460471301, 31381236756, 94143533121, 282430067922, 847289672325, 2541867422652, 7625600673633 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
C. G. Bower, Transforms (2)
FORMULA
a(n) = (1/6)*((5-(-1)^n)*3^floor(n/2) + 2*3^n). - Ralf Stephan, May 11 2004
a(n) = 3*a(n-1)+3*a(n-2)-9*a(n-3). G.f.: -x*(9*x^2+x-2) / ((3*x-1)*(3*x^2-1)). - Colin Barker, Dec 15 2012
MATHEMATICA
CoefficientList[Series[-(9 x^2 + x - 2)/((3 x - 1) (3 x^2 - 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 19 2013 *)
PROG
(Magma) [(1/6)*((5-(-1)^n)*3^Floor(n/2) + 2*3^n): n in [1..30]]; // Vincenzo Librandi, Oct 19 2013
CROSSREFS
Sequence in context: A292212 A212823 A292213 * A292214 A292215 A292216
KEYWORD
nonn,easy,changed
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Oct 19 2013
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 March 19 06:05 EDT 2024. Contains 370952 sequences. (Running on oeis4.)