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A173933 The number of numbers m < k/2 such that m/k is a reduced fraction in the Cantor set, where k= A173931(n). 3
1, 2, 3, 3, 4, 8, 6, 15, 6, 6, 8, 15, 8, 12, 8, 8, 10, 24, 27, 16, 12, 9, 63, 10, 16, 12, 63, 20, 12, 11, 10, 36, 12, 56, 12, 12, 44, 12, 15, 36, 12, 16, 120, 60, 110, 24, 16, 18, 24, 225 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

When k is a prime of the form (3^r-1)/2, then the m are 2^r-1 numbers (greater than 0) whose base-3 representation consists of only 0's and 1's. Hence, for r=3,7, and 13, the primes k are 13, 1093, and 797161, and the number of m < k/2 is 3, 63, and 4095.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..185

EXAMPLE

When k=40, then 1/k, 3/k, 9/k, and 13/k have base-3 representations containing only the digits 0 and 2.

MATHEMATICA

Length /@ Last[Transpose[cantor]] (* see A173931 *)

CROSSREFS

Cf. A005823, A005836, A007734, A076481, A173931, A173934.

Sequence in context: A239849 A202560 A227165 * A193821 A130743 A263775

Adjacent sequences:  A173930 A173931 A173932 * A173934 A173935 A173936

KEYWORD

nonn

AUTHOR

T. D. Noe, Mar 03 2010

EXTENSIONS

Name qualified by Peter Munn, Jul 14 2019

STATUS

approved

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Last modified October 16 21:10 EDT 2019. Contains 328103 sequences. (Running on oeis4.)