OFFSET
1,1
COMMENTS
23 is in sequence because 2*3+1=7 and 2*3-1=5; 41 because 4*1+1=5 and 4*1-1=3.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Prime[Range[5000]], PrimeQ[Times@@IntegerDigits[#] - 1] && PrimeQ[Times@@IntegerDigits[#] + 1] &] (* Vincenzo Librandi, Feb 15 2014 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Oct 28 2009
EXTENSIONS
Corrected (29 inserted) and extended beyond 659 by R. J. Mathar, Nov 30 2009
STATUS
approved