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 A187819 #15 Mar 12 2023 08:49:46 %S A187819 3,7,13,19,307,619,2089,7297,75571,76103,98897 %N A187819 Numbers k such that (9^k + 8^k)/17 is prime. %C A187819 All terms are prime. %C A187819 a(12) > 10^5. %t A187819 Select[ Prime[ Range[1, 100000] ], PrimeQ[ (9^# + 8^#)/17 ]& ] %o A187819 (PARI) is(n)=isprime((9^n+8^n)/17) \\ _Charles R Greathouse IV_, Feb 17 2017 %Y A187819 Cf. A181141, A128339, A057175, A125956. %K A187819 nonn,hard,more %O A187819 1,1 %A A187819 _Robert Price_, Dec 26 2012