A162813 a(n) = 3*a(n-2) for n > 2; a(1) = 5, a(2) = 3.

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, 645700815, 387420489

Offset

1,1

Comments

Binomial transform is A162562.

Links

Table of n, a(n) for n=1..36.

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

Formula

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

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

Mathematica

nxt[{a_, b_}]:={b, 3a}; NestList[nxt, {5, 3}, 40][[All, 1]] (* or *) LinearRecurrence[ {0, 3}, {5, 3}, 40] (* Harvey P. Dale, May 29 2021 *)

Prog

(Magma) [ n le 2 select 7-2*n else 3*Self(n-2): n in [1..34] ];

Crossrefs

Cf. A162562, A162436, A162766.

Sequence in context: A298975 A070375 A166465 * A146934 A213762 A178067

Adjacent sequences: A162810 A162811 A162812 * A162814 A162815 A162816

Keyword

nonn,easy

Author

Klaus Brockhaus, Jul 20 2009

Extensions

a(35)-a(36) from Yifan Xie, Jul 20 2022

Status

approved