A028842 Numbers whose product of digits is prime.

2, 3, 5, 7, 12, 13, 15, 17, 21, 31, 51, 71, 112, 113, 115, 117, 121, 131, 151, 171, 211, 311, 511, 711, 1112, 1113, 1115, 1117, 1121, 1131, 1151, 1171, 1211, 1311, 1511, 1711, 2111, 3111, 5111, 7111, 11112, 11113, 11115, 11117, 11121, 11131, 11151

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..130

Index entries for 10-automatic sequences

Mathematica

Select[Range[11160], PrimeQ[Times@@IntegerDigits[#]] &] (* Jayanta Basu, Jun 02 2013 *)

Prog

(SageMath) [x for x in range(10^5) if (prod(Integer(x).digits(base=10))) in Primes()] # Bruno Berselli, May 05 2014
(Scala) (1 to 10000).filter(n => List(2, 3, 5, 7).contains(n.toString.toCharArray.map(_ - 48).scanRight(1)(_ * _).head)) // Alonso del Arte, Apr 14 2020
(PARI) isok(n) = isprime(vecprod(digits(n))); \\ Michel Marcus, Apr 17 2020
(PARI) is(n)=my(d=digits(n), p); for(i=1, #d, if(d[i]==1, next); if(isprime(d[i]) && !p, p=1, return(0))); p \\ Charles R Greathouse IV, Apr 18 2020

Crossrefs

Cf. A007954, A028843, A028834, A046703 (subsequence of primes).

Sequence in context: A344451 A092620 A028843 * A260181 A140971 A073689

Adjacent sequences: A028839 A028840 A028841 * A028843 A028844 A028845

Keyword

nonn,base,easy

Author

N. J. A. Sloane

Extensions

More terms from Erich Friedman.

Name edited by Jianing Song, Jul 07 2025

Status

approved