A037439 Positive numbers having the same set of digits in base 7 and base 9.

1, 2, 3, 4, 5, 6, 31, 99, 198, 248, 297, 749, 1163, 1471, 1498, 1577, 1831, 2247, 3413, 3988, 4473, 4491, 4500, 4509, 4788, 4789, 4790, 4791, 4792, 4793, 4794, 6769, 7311, 7626, 7698, 7726, 8290, 8299, 8535, 9005, 9038, 9122, 9172, 9185, 9192, 9199, 9248, 9801

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Examples

			198 is in the sequence because 198 in base 7 is 402 and in base 9 it is 240.
		

Links

• John Cerkan, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A037403.

Cf. A007093, A007095.

Programs

Mathematica

Select[Range[10^4], Union@ IntegerDigits[#, 7] == Union@ IntegerDigits[#, 9] &] (* Michael De Vlieger, Feb 18 2017 *)

PARI

isok(n) = Set(digits(n, 7)) == Set(digits(n, 9)); \\ Michel Marcus, Feb 18 2017

Extensions

More terms from Don Reble, Apr 28 2006

Edited by John Cerkan, Feb 17 2017