OFFSET
1,1
LINKS
Robert Price, Table of n, a(n) for n = 1..2779
Index to Primes, Primes that become a different prime under some mapping.
MATHEMATICA
fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 4] || MemberQ[id, 7]) && PrimeQ[ FromDigits[ id /. {4 -> 7, 7 -> 4}] ]]; Select[ Prime@ Range@ 300, fQ]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Zak Seidov and Robert G. Wilson v, Sep 09 2010
STATUS
approved