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A168570 Exponent of 3 in 2^n - 1. 2
0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 4, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

Records: a(A025192(n)) = n and a(k) < n for k < A025192(n). [Joerg Arndt, Apr 07 2014]

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

EXAMPLE

For n=6, 2^6 - 1 = 63. Greatest divisor of 63 which is a power of 3 is 9 (3^2).

MAPLE

a:= n-> padic[ordp](2^n-1, 3):

seq(a(n), n=1..120); # Alois P. Heinz, Mar 27 2017

MATHEMATICA

Table[IntegerExponent[2^n - 1, 3], {n, 100}] (* T. D. Noe, Apr 13 2014 *)

PROG

(PARI) vector(100, n, valuation(2^n-1, 3)) /* Joerg Arndt, Jun 13 2011 */

CROSSREFS

Cf. A051064 (without the zeros).

Sequence in context: A248908 A133565 A239704 * A340928 A355742 A267860

Adjacent sequences: A168567 A168568 A168569 * A168571 A168572 A168573

KEYWORD

nonn

AUTHOR

Martins Opmanis, Nov 30 2009

STATUS

approved

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Last modified February 1 08:00 EST 2023. Contains 359981 sequences. (Running on oeis4.)