The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A170951 Numbers n with the property that some of the fractions i/n (with gcd(i,n)=1, 0 < i/n < 1) are in the Cantor set and some are not. 4

%I

%S 9,12,13,27,28,30,36,39,40,81,82,84,90,91,108,117,120,121,243,244,246,

%T 252,270,273,324,328,351,360,363,364,729,730,732,738,756,757,810,819,

%U 820,949,972,984,1036,1053,1080,1089,1092,1093,2187

%N Numbers n with the property that some of the fractions i/n (with gcd(i,n)=1, 0 < i/n < 1) are in the Cantor set and some are not.

%C Equals A054591 \ {1,3,4,10}.

%C The natural numbers may be divided into three sets: denominators which force membership in the Cantor set, denominators which deny membership in the Cantor set and denominators which neither force nor deny membership. The first set contains just the numbers 1, 3, 4, 10. The second set is A170944. The third set is the present sequence.

%e 1/9 is in the Cantor set, but 4/9 is not.

%Y Cf. A005823, A005836, A054591, A121153, A170943, A170944.

%K nonn,base

%O 1,1

%A _J. H. Conway_ and _N. J. A. Sloane_, Feb 20 2010

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

Last modified June 20 06:23 EDT 2021. Contains 345157 sequences. (Running on oeis4.)