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 A058958 #66 Oct 02 2024 12:33:52
%S A058958 0,1,2,3,6,9,10,22,30,42,57,87,174,195,198,562,994,2421,2487,4629,
%T A058958 5838,13698,14730,16966,25851,98634,117222,192819,226038,296115,
%U A058958 318465,355902
%N A058958 Numbers k such that 3^k + 4 is prime.
%C A058958 Next term > 15000. The primes corresponding to 4629, ..., 14730 pass PARI's ispseudoprime() and the Rabin-Miller test for the first 100 prime bases. - _Joerg Arndt_, Jul 19 2012
%C A058958 Used PFGW (Fermat and Lucas, BLS) to determine (probable) primality of a(24)-a(26). - _Robert Price_, Jun 30 2013
%C A058958 a(27) > 10^5. - _Robert Price_, Jun 30 2013
%C A058958 a(29) > 2*10^5. - _Robert Price_, Dec 10 2013
%C A058958 a(31) > 3*10^5. - _Tyler NeSmith_, Dec 10 2020
%t A058958 Do[ If[ PrimeQ[3^n + 4], Print[n] ], {n, 0, 3000} ]
%t A058958 Select[Range[0,3000],PrimeQ[3^#+4]&] (* _Harvey P. Dale_, Sep 07 2022 *)
%o A058958 (PARI) for(n=0,10^5,if(ispseudoprime(3^n+4),print1(n,", "))); /* _Joerg Arndt_, Jul 19 2012 */
%o A058958 (Magma) [n: n in [0..700] | IsPrime(3^n+4)]; // _Vincenzo Librandi_, Aug 25 2015
%Y A058958 Cf. A102903 (corresponding primes).
%K A058958 nonn,hard,more
%O A058958 1,3
%A A058958 _Robert G. Wilson v_, Jan 13 2001
%E A058958 Terms 4629 ... 14730 from _Joerg Arndt_, Jul 19 2012
%E A058958 0 added by _Bruno Berselli_, Oct 04 2012
%E A058958 a(24)-a(26) from _Robert Price_, Jun 30 2013
%E A058958 a(27)-a(28) from _Robert Price_, Dec 10 2013
%E A058958 a(29)-a(30) from _Tyler NeSmith_, Dec 10 2020
%E A058958 a(31)-a(32) from _Aurelien Gibier_, Oct 02 2024