A175637 Numbers n such that the decimal digits of n are not present in k*n, k=2..9.

1, 3, 7, 9, 11, 77, 111, 707, 777, 909, 1111, 7777, 11111, 70707, 77777, 90909, 111111, 777777, 1111111, 7070707, 7777777, 9090909, 11111111, 77777777, 111111111, 707070707, 777777777, 909090909, 1111111111, 7777777777, 11111111111

Offset

1,2

Comments

There are four infinite patterns 1..1, 7..7, 7070..7 & 9090..9.

Links

Table of n, a(n) for n=1..31.

Example

7777*(1..9)= 7777,15554,23331,31108,38885,46662,54439,62216,69993.

Mathematica

fQ[n_] := Intersection[ IntegerDigits@n, Union@ Flatten[ IntegerDigits[n* Range[2, 9]]]] == {}; k = 1; lst = {}; While[k < 10^9, If[ fQ@k, AppendTo[lst, k]]; k++ ]; lst

Crossrefs

A140467

Sequence in context: A263926 A114788 A085074 * A110404 A366529 A190366

Adjacent sequences: A175634 A175635 A175636 * A175638 A175639 A175640

Keyword

base,nonn

Author

Zak Seidov, Aug 01 2010

Extensions

Corrected and extended the sequence, changed the comment line and added the Mathematica coding Robert G. Wilson v, Aug 03 2010

Status

approved