This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A321420 #16 Dec 14 2018 19:44:25
%S A321420 2,3,5,7,11,13,17,31,71,73,101,107,113,131,149,157,167,179,181,191,
%T A321420 199,311,347,353,359,389,701,733,739,743,751,761,787,797,919,941,953,
%U A321420 967,971,983,991,1009,1021,1031,1061,1091,1097,1103,1109,1151,1153,1217,1223
%N A321420 Primes p whose reversal is a Chen prime.
%C A321420 73 is the smallest non-Chen prime whose reversal is a Chen prime.
%e A321420 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).
%t A321420 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 *)
%o A321420 (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
%Y A321420 Cf. A118725, A109611, A102540.
%K A321420 nonn,base
%O A321420 1,1
%A A321420 _Paolo Galliani_, Nov 09 2018