A140429 a(n) = floor(3^(n-1)).

0, 1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683, 59049, 177147, 531441, 1594323, 4782969, 14348907, 43046721, 129140163, 387420489, 1162261467, 3486784401, 10460353203, 31381059609, 94143178827, 282429536481, 847288609443

Offset

0,3

Comments

Binomial transform of Jacobsthal numbers A001045.

Implicit use in A094555 (Barry).

Links

Table of n, a(n) for n=0..26.

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

Formula

a(n) = floor(3^(n-1)) = A000244(n-1) = A133494(n), n >= 1.

O.g.f.: x/(1-3x). - R. J. Mathar, Aug 27 2008

Prog

(PARI) a(n)=if(n<2, n, 3^(n-1)) \\ Charles R Greathouse IV, Oct 03 2016
(PARI) a(n)=floor(3^(n-1)) \\ M. F. Hasler, Apr 13 2018

Crossrefs

Cf. A000079, A131577, A133494.

Sequence in context: A216097 A243845 A354269 * A141413 A000244 A133494

Adjacent sequences: A140426 A140427 A140428 * A140430 A140431 A140432

Keyword

nonn,easy

Author

Paul Curtz, Jun 19 2008

Extensions

Extended by R. J. Mathar, Aug 28 2008

New name by M. F. Hasler, Apr 13 2018

Status

approved