The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A062239 Numbers n with property that every digit is a prime factor of n. 2


%S 2,3,5,7,22,33,55,77,222,333,555,735,777,2222,2232,2322,2772,3222,

%T 3333,3555,5355,5535,5555,5775,7777,22222,22332,22722,23232,23322,

%U 23772,27272,32232,32322,33222,33333,33555,35355,35535,37737,53355,53535

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

%C 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

%H Harry J. Smith and Charles R Greathouse IV, <a href="/A062239/b062239.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Smith)

%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>

%e 77322 is divisible by 7, 3 and 2.

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

%o (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

%K base,easy,nonn

%O 1,1

%A _Erich Friedman_, Jun 30 2001

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 5 06:51 EST 2020. Contains 338944 sequences. (Running on oeis4.)