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 A344360 #46 Nov 01 2021 01:15:54
%S A344360 2,3,5,7,13,53,67,83,167,1367,2473,4789,34127,219217
%N A344360 Primes p such that (2^p - 2)/p + 1 is prime.
%C A344360 a(15) > 1099997, if it exists. - _Karl-Heinz Hofmann_, Jul 27 2021
%C A344360 These are primes p such that 2^((2^p-2)/p) == 1 (mod (2^p-2)/p+1) if and only if there are no pseudoprimes of the form (2^q-2)/q+1 with q prime. - _Thomas Ordowski_, Aug 29 2021
%e A344360 7 is a term because (2^7 - 2)/7 + 1 = 19 is prime.
%t A344360 Select[Prime@ Range[10^3], PrimeQ[(2^# - 2)/# + 1] &] (* _Michael De Vlieger_, Oct 12 2021 *)
%o A344360 (PARI) lista(lim)={forprime(p=1,lim,if(ispseudoprime((2^p-2)/p+1), print1(p,", ")))}
%o A344360 (PARI) c3(p) = {s=3; for(x=1, p, s=(s^2)%((2^p-2)/p+1)); if(s==9, print1(p, ", "))} /* PRP Test */
%Y A344360 Cf. A064535, A344361.
%K A344360 nonn,more
%O A344360 1,1
%A A344360 _Jorge Coveiro_, May 15 2021
%E A344360 a(14) from _Karl-Heinz Hofmann_, Jun 11 2021