login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A173931 Primitive numbers k such that m/k is in the Cantor set for some m. 4
4, 10, 13, 28, 40, 82, 91, 121, 146, 182, 205, 244, 328, 364, 386, 656, 671, 730, 757, 820, 949, 1036, 1093, 1342, 1640, 2044, 2188, 2362, 2555, 2644, 2684, 2812, 2920, 3280, 3640, 3796, 3851, 4088, 4561, 4745, 5110, 6176, 6562, 6643, 7381, 7592, 7913 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primitive means no k is a multiple of 3. This is sequence A054591 without the multiples of 3. Sequence A173793 is a subsequence. Sequence A173932 gives the least m such for each k. Sequence A173933 gives the number of m < k/2 such that m/k is in the Cantor set. Irregular triangle A173934 gives a row of m values for each k.

The remaining terms <10000 are 9139, 9490, 9841.

It is assumed that gcd(m,k) = 1.

LINKS

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

MATHEMATICA

InCantorQ[m_, n_] := !MemberQ[Union[Flatten[RealDigits[m/n, 3][[1]]]], 1]; cantor=Reap[Do[If[Mod[n, 3] > 0, s=Select[Range[Ceiling[n/2]], GCD[n, # ]==1 && InCantorQ[ #, n] &]; If[s != {}, Sow[{n, s}]]], {n, 10000}]][[2, 1]]; First[Transpose[cantor]]

CROSSREFS

Sequence in context: A139121 A079932 A191107 * A173793 A076270 A032821

Adjacent sequences:  A173928 A173929 A173930 * A173932 A173933 A173934

KEYWORD

nonn

AUTHOR

T. D. Noe, Mar 03 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified July 22 03:22 EDT 2017. Contains 289648 sequences.