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 A171058 #20 Jul 25 2024 07:42:04 %S A171058 0,1,3,41,45,83,95,181,193,195,311,325,901,1825,3649,7709,16335,45547 %N A171058 Numbers k such that 3^k + 3*k + 1 is prime. %C A171058 a(19) > 10^5. - _Michael S. Branicky_, Jul 25 2024 %o A171058 (PARI) is(n)=ispseudoprime(3^n+3*n+1) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A171058 Numbers k such that b^k + b*k + 1 is prime: A301634 (b=2), this sequence (b=3), A301635 (b=5). %Y A171058 Cf. A176805, A180269. %K A171058 nonn,more %O A171058 1,3 %A A171058 _N. J. A. Sloane_, Sep 04 2010, based on a posting to the Sequence Fans Mailing List by _Charles R Greathouse IV_, Aug 23 2010 %E A171058 More terms from _Charles R Greathouse IV_, Sep 07 2010