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!)
A166465 a(n) = 3*a(n-2) for n > 2; a(1) = 1, a(2) = 5. 1
1, 5, 3, 15, 9, 45, 27, 135, 81, 405, 243, 1215, 729, 3645, 2187, 10935, 6561, 32805, 19683, 98415, 59049, 295245, 177147, 885735, 531441, 2657205, 1594323, 7971615, 4782969, 23914845, 14348907, 71744535, 43046721, 215233605, 129140163 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Interleaving of A000244 and A005030.

Second binomial transform is A054485. Fifth binomial transform is A153596.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0, 3).

FORMULA

a(n) = (4+(-1)^n)*3^(1/4*(2*n-5+(-1)^n)).

G.f.: x*(1+5*x)/(1-3*x^2).

PROG

(MAGMA) [ n le 2 select 4*n-3 else 3*Self(n-2): n in [1..35] ];

CROSSREFS

Equals A162813 preceded by 1.

Cf. A000244 (powers of 3), A005030 (5*3^n), A054485, A153596.

Sequence in context: A298975 A070375 A162813 * A146934 A213762 A178067

Adjacent sequences:  A166462 A166463 A166464 * A166466 A166467 A166468

KEYWORD

nonn,easy

AUTHOR

Klaus Brockhaus, Oct 14 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 20 12:58 EDT 2021. Contains 343135 sequences. (Running on oeis4.)