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A210546
Emirps whose products of digits are prime.
3
13, 17, 31, 71, 113, 311, 1151, 1511, 111211, 112111, 1111711, 1171111, 11111117, 11113111, 11131111, 71111111, 111111131, 131111111, 1111115111, 1115111111, 11111111113, 31111111111, 111111111111111131, 131111111111111111, 1111111111111111111111111511
OFFSET
1,1
LINKS
PROG
(Python)
from __future__ import division
from sympy import isprime
A210546_list = []
for l in range(1, 20):
q = (10**l-1)//9
for i in range(l):
for p in [2, 3, 5, 7]:
r = q+(p-1)*10**i
s, t = str(r), str(r)[::-1]
if s != t and isprime(r) and isprime(int(t)):
A210546_list.append(r) # Chai Wah Wu, Aug 15 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, Mar 22 2012
EXTENSIONS
5 more terms from Alois P. Heinz, Mar 29 2012
STATUS
approved