OFFSET
1,1
COMMENTS
The second term of the sequence: 733 is congruent to 1 mod 61, to 2 mod 43, to 3 mod 73, where 61 is the second non-Chen prime, 43 is the first non-Chen prime and 73 is the third non-Chen prime. 733 is also congruent to 4 mod (3^6).
MATHEMATICA
cpQ[n_] := Module[{rev = FromDigits[Reverse[IntegerDigits[n]]]}, PrimeOmega[n + 2] > 2 && PrimeQ[rev] && PrimeOmega[rev + 2] < 3]; Select[Prime[Range[1300]], cpQ] (* Amiram Eldar, Nov 09 2018 after Harvey P. Dale at A118725 *)
PROG
(PARI) forprime(p=1, 10^4, w=Vecrev(digits(p)); q=0; for(j=1, length(w), q=q*10+w[j]); if(ispseudoprime(q)==1, if(bigomega(p+2)>2, if(bigomega(q+2)<=2, print1(p, ", ")))))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paolo Galliani, Nov 09 2018
STATUS
approved