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 A215445 #23 Jul 12 2018 11:33:13 %S A215445 1,11,65,133,679,1571,27517,51631 %N A215445 Numbers k such that 7^k + k^7 - 1 is prime. %C A215445 a(9) > 10^5. - _Robert Price_, Feb 23 2014 %t A215445 Select[Range[0, 5000], PrimeQ[7^# + #^7 - 1] &] %o A215445 (PARI) is(n)=ispseudoprime(7^n+n^7-1) \\ _Charles R Greathouse IV_, Jun 06 2017 %Y A215445 Cf. A100357, A215434-A215444, A216375. %K A215445 nonn,hard,more %O A215445 1,2 %A A215445 _Vincenzo Librandi_, Sep 06 2012 %E A215445 a(7)-a(8) from _Robert Price_, Feb 23 2014