login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A189737 a(1)=3,  a(2)=3, a(n)=3*a(n-1) + 3*a(n-2) 12
3, 3, 18, 63, 243, 918, 3483, 13203, 50058, 189783, 719523, 2727918, 10342323, 39210723, 148659138, 563609583, 2136806163, 8101247238, 30714160203, 116446222323, 441481147578, 1673782109703, 6345789771843, 24058715644638, 91213516249443, 345816695682243 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..100

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

FORMULA

a(n)=3/2*((3/2+1/2*sqrt(21))^(n-1)+(3/2-1/2*sqrt(21))^(n-1)+1/14*sqrt(21)*((3/2-1 /2*sqrt(21))^(n-1)-(3/2+1/2*sqrt(21))^(n-1)). - Paolo P. Lava, May 24 2011

G.f.: 3*x*(1-2*x)/(1-3*x-3*x^2). - Bruno Berselli, May 24 2011

MATHEMATICA

LinearRecurrence[{3, 3}, {3, 3}, 40]

PROG

(Maxima) a[1]:3$ a[2]:3$ a[n]:=3*a[n-1]+3*a[n-2]$ makelist(a[n], n, 1, 26);  [Bruno Berselli, May 24 2011]

CROSSREFS

Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189736, A189738, A189739, A189741, A189742, A189743, A189744, A189745, A189746, A189747, A189748, A189749.

Sequence in context: A183039 A192527 A227773 * A261567 A096935 A136475

Adjacent sequences:  A189734 A189735 A189736 * A189738 A189739 A189740

KEYWORD

nonn

AUTHOR

Harvey P. Dale, Apr 26 2011

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 10 17:00 EDT 2021. Contains 342852 sequences. (Running on oeis4.)