A292125 Positive numbers n such that the set of base-7 digits of n equals both the set of base-8 digits of n and the set of base-9 digits of n.

1, 2, 3, 4, 5, 6, 32942, 103302, 142489, 178248, 263180, 361369, 362370, 378454, 540929, 540940, 567333, 567337, 590697, 693302, 723659, 726195, 743217, 829792, 888934, 1070221, 1073830, 1074177, 1083411, 1083738, 1090352, 1106956, 1129738, 1139557, 1139881, 1201762, 1249562

Offset: 1

Author

Paul Lusch, Sep 08 2017

Keywords

• nonn
• base

Examples

			32942 in base 7 is 165020; in base 8 is 100256; and in base 9 is 50162. The set of digits for all three is {0, 1, 2, 5, 6}.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..1000

Crossrefs

Subsequence of A037438.

Programs

Maple

filter:= proc(n) local S;
  S:= convert(convert(n,base,9),set);
  nops(S intersect {7,8})=0 and evalb(convert(convert(n,base,8),set)=S) and evalb(convert(convert(n,base,7),set)=S)
end proc:
select(filter, [$1..6,seq(seq(9*a+b,b=0..6),a=1..7*9^5-1)]); # Robert Israel, Sep 11 2017

Mathematica

Select[Range[5/4*10^6], Function[k, SameQ @@ Map[Union@ IntegerDigits[k, #] &, {7, 8, 9}]]] (* Michael De Vlieger, Sep 10 2017 *)

PARI

isok(n) = my(s7 = Set(digits(n, 7)), s8 = Set(digits(n, 8)), s9 = Set(digits(n, 9))); (s7 == s8) && (s8 == s9); \\ Michel Marcus, Sep 09 2017

Extensions

More terms from Michel Marcus, Sep 09 2017