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

Author

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

Keywords

• nonn
• base

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.

Examples

			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.
		

Links

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

Crossrefs

Cf. A005823, A005836, A121153, A170951.