A062153 a(n) = floor(log_3(n)).

0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4

Offset

1,9

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Formula

a(n) = (number of digits of n when written in base 3) - 1.

a(n) = if n > 2 then a(floor(n / 3)) + 1 else 0. - Reinhard Zumkeller, Oct 29 2001

G.f.: (1/(1 - x))*Sum_{k>=1} x^(3^k). - Ilya Gutkovskiy, Jan 08 2017

Mathematica

Floor[Log[3, Range[120]]]  (* Harvey P. Dale, Apr 30 2011 *)

Prog

(Magma) [ Ilog(3, n) : n in [1..100] ]; // N. J. A. Sloane, Dec 23 2006
(PARI) default(realprecision, 100); t=1/log(3); for (n=1, 1000, write("b062153.txt", n, " ", floor(t*log(n) + 0.0000001)) ) \\ Harry J. Smith, Aug 02 2009
(PARI) a(n)=logint(n, 3) \\ Charles R Greathouse IV, Nov 15 2022

Crossrefs

Cf. A000244, A000523, A007089, A102572.

Sequence in context: A214081 A194338 A176170 * A217693 A204560 A135661

Adjacent sequences: A062150 A062151 A062152 * A062154 A062155 A062156

Keyword

easy,nonn

Author

Henry Bottomley, Jun 06 2001

Status

approved