A062239 Numbers n with property that every digit is a prime factor of n.

2, 3, 5, 7, 22, 33, 55, 77, 222, 333, 555, 735, 777, 2222, 2232, 2322, 2772, 3222, 3333, 3555, 5355, 5535, 5555, 5775, 7777, 22222, 22332, 22722, 23232, 23322, 23772, 27272, 32232, 32322, 33222, 33333, 33555, 35355, 35535, 37737, 53355, 53535

Offset

1,1

Comments

This is a regular language in base 10. Almost all members of this sequence are multiples of either 42 or 105. There are about 2/63 * 3^n members of this sequence up to 10^n. - Charles R Greathouse IV, Nov 09 2011

Links

Harry J. Smith and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 1000 terms from Smith)

Index entries for 10-automatic sequences

Example

77322 is divisible by 7, 3 and 2.

Mathematica

Select[Range[2, 50000], Complement[IntegerDigits[#], FactorInteger[#][[All, 1]]] == {} &] (* Alonso del Arte, Dec 05 2011 *)

Prog

(PARI) { n=0; for (m=1, 10^10, t=m; b=1; while (t>0, d=t%10; t=(t-d)/10; if (!isprime(d) || m%d, b=0; break)); if (b, write("b062239.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 17 2010

Crossrefs

Sequence in context: A062087 A162457 A084983 * A066483 A114420 A349899

Adjacent sequences: A062236 A062237 A062238 * A062240 A062241 A062242

Keyword

base,easy,nonn

Author

Erich Friedman, Jun 30 2001

Status

approved