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A229221 Numbers k such that k - (product of digits of k) is prime.

%I A229221 #32 Jul 28 2025 20:18:45
%S A229221 21,23,27,29,41,43,47,49,81,83,87,89,101,103,107,109,127,141,143,149,
%T A229221 181,187,223,227,229,241,247,251,253,263,271,277,293,299,307,343,347,
%U A229221 349,367,383,389,401,409,413,417,419,431,433,437,439,451,457,471,473,477,479,481,487,503,509,527,529,541
%N A229221 Numbers k such that k - (product of digits of k) is prime.
%t A229221 fQ[n_] := Module[{q = n - Times @@ IntegerDigits[n]}, q > 0 && PrimeQ[q]]; Select[Range[500], fQ] (* _T. D. Noe_, Sep 17 2013 *)
%o A229221 (Python)
%o A229221 from sympy import isprime
%o A229221 def DP(n):
%o A229221     p = 1
%o A229221     for i in str(n):
%o A229221         p *= int(i)
%o A229221     return p
%o A229221 {print(n,end=', ') for n in range(10**3) if isprime(n-DP(n))}
%o A229221 ## Simplified by _Derek Orr_, Apr 10 2015
%o A229221 (Sage)
%o A229221 [x for x in range(1000) if (x-prod(Integer(x).digits(base=10))) in Primes()] # _Tom Edgar_, Sep 18 2013
%o A229221 (PARI) for(n=1,10^3,d=digits(n);p=prod(i=1,#d,d[i]);if(isprime(n-p),print1(n,", "))) \\ _Derek Orr_, Apr 10 2015
%Y A229221 Cf. A157676.
%K A229221 nonn,base,easy
%O A229221 1,1
%A A229221 _Derek Orr_, Sep 16 2013
%E A229221 More terms from _Derek Orr_, Apr 10 2015