OFFSET
1,1
COMMENTS
73 is the smallest non-Chen prime whose reversal is a Chen prime.
EXAMPLE
73 is in the sequence because its reversal is 37 which is a Chen prime (because 37 + 2 = 39 has at most two prime factors).
MATHEMATICA
cpQ[n_] := Module[{rev = FromDigits[Reverse[IntegerDigits[n]]]}, PrimeQ[rev] && PrimeOmega[rev + 2] < 3]; Select[Prime[Range[400]], cpQ] (* Amiram Eldar, Nov 09 2018 after Harvey P. Dale at A118725 *)
PROG
(PARI) is(n) = if(isprime(n), rn = fromdigits(Vecrev(digits(n))); return(isprime(rn) && bigomega(rn+2) <= 2), 0) \\ David A. Corneth, Nov 09 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paolo Galliani, Nov 09 2018
STATUS
approved