OFFSET
1,1
EXAMPLE
527 is a semiprime and its non-repeating digits are primes.
MATHEMATICA
Select[FromDigits/@Flatten[Permutations/@Subsets[ {2, 3, 5, 7}], 1], PrimeOmega[ #] == 2&]//Union
CROSSREFS
KEYWORD
easy,base,fini,full,nonn
AUTHOR
Harvey P. Dale, Sep 08 2021
STATUS
approved