OFFSET
1,1
EXAMPLE
31 is in the sequence because (1) it is a Chen prime and (2) the product of its digits 3*1=3 is also a Chen prime.
MATHEMATICA
chenQ[n_]:=Module[{pidn=Times@@IntegerDigits[n]}, PrimeQ[pidn]&&PrimeOmega[ pidn+2]<3]; With[{chen=Select[Prime[Range[4200000]], PrimeOmega[#+2]<3&]}, Select[chen, chenQ]] (* Harvey P. Dale, Apr 22 2012 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), May 21 2006
STATUS
approved