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A122586 Leading digit of n expressed in base 3. 3
1, 2, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Values 1 and 2 appear alternately and each time in runs whose lengths are the powers of 3. Each power of 3 is used twice: once for a run of 1's and then for a run of 2's.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = floor(n/(3^floor(log(n)/log(3)))).

From Robert Israel, Mar 15 2017: (Start)

a(3n) = a(3n+1) = a(3n+2) = a(n).

G.f.: g(x) satisfies g(x) = x + 2 x^2 + (1+x+x^2) g(x^3). (End)

EXAMPLE

a(1) = 1/(3^0) = 1.

MAPLE

seq( evalf(floor(n/ (3^floor(log[3](n))))), n=1..500);

CROSSREFS

Sequence in context: A145705 A029339 A029364 * A079487 A229122 A069010

Adjacent sequences:  A122583 A122584 A122585 * A122587 A122588 A122589

KEYWORD

easy,nonn,base

AUTHOR

Peter C. Heinig (algorithms(AT)gmx.de), Oct 20 2006

EXTENSIONS

Name changed by Franklin T. Adams-Watters, Sep 29 2011

STATUS

approved

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Last modified March 21 04:59 EDT 2019. Contains 321364 sequences. (Running on oeis4.)