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 A302987 #21 Apr 17 2018 06:59:56 %S A302987 3,7,727,1595287,3773335151,53968982887,218662611751,373627441111, %T A302987 525882352087,612618285511 %N A302987 Primes p such that p+3 divides 3^p+3. %C A302987 Conjecture: the sequence is finite. %C A302987 Is this the same as the primes in A251862? - _Michel Marcus_, Apr 17 2018 %C A302987 a(11) > 10^12, if it exists. - _Giovanni Resta_, Apr 17 2018 %t A302987 Select[Prime[Range[10000]], Divisible[3^# + 3, # + 3] &] (* _Vincenzo Librandi_, Apr 17 2018 *) %o A302987 (PARI) isok(p) = isprime(p) && (Mod(3,p+3)^p == Mod(-3,p+3)); \\ _Michel Marcus_, Apr 17 2018 %Y A302987 Cf. A000040, A000244, A302988. %K A302987 nonn,hard,more %O A302987 1,1 %A A302987 _Alex Ratushnyak_, Apr 17 2018 %E A302987 a(4)-a(5) from _Michel Marcus_, Apr 17 2018 %E A302987 a(6)-a(10) from _Giovanni Resta_, Apr 17 2018