A170943 Numbers n with the property that when 1/n is written in base 3 (in either of the two representations, if the representation is ambiguous) the fractional part contains no 1's.

1, 4, 10, 12, 13, 28, 30, 36, 39, 40, 82, 84, 90, 91, 108, 117, 120, 121, 244, 246, 252, 270, 273, 324, 328, 351, 360, 363, 364, 730, 732, 738, 756, 757, 810, 819, 820, 949, 972, 984, 1036, 1053, 1080, 1089, 1092, 1093, 2188, 2190, 2196, 2214, 2268, 2271, 2362, 2430

Offset

1,2

Comments

That is, neither of the two representations of 1/n in base 3 contain a 1.

This is A121153 without the numbers 3^k, k >= 1. See that entry for further information.

Links

T. D. Noe and N. J. A. Sloane, Table of n, a(n) for n=1..1144 (terms < 3^21)

Example

1/3 in base 3 can be written as either .1 or .0222222... The first version contains a 1, so 3 is not in the sequence.
1/4 in base 3 is .02020202020..., so 4 is in the sequence.

Crossrefs

Cf. A005823, A005836, A121153, A170951.

Sequence in context: A370859 A355275 A092428 * A102998 A071179 A155475

Adjacent sequences: A170940 A170941 A170942 * A170944 A170945 A170946

Keyword

nonn,base

Author

J. H. Conway, T. D. Noe and N. J. A. Sloane, Feb 20 2010

Status

approved