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 A096594 #19 Dec 15 2017 17:36:44 %S A096594 1,2,3,5,6,7,9,13,26,42,153,188,204,282,699,2886,11597 %N A096594 Numbers n such that 100^n + 10^n - 1 is prime. %C A096594 a(1) through a(17) have been proved to be prime with WinPFGW or pfgw. %C A096594 a(18) > 20000. - _Giovanni Resta_, Feb 19 2013 %C A096594 a(18) > 100000. - _James G. Merickel_ Jun 02 2014 %e A096594 a(3) = 3 because 100^3 + 10^3 - 1 = 1000999, a prime. %t A096594 Select[Range[700], PrimeQ[100^# + 10^# - 1] & ] (* _Giovanni Resta_, Feb 19 2013 *) %o A096594 (PARI) is(n)=ispseudoprime(100^n+10^n-1) \\ _Charles R Greathouse IV_, Feb 20 2017 %K A096594 more,nonn %O A096594 1,2 %A A096594 _Jason Earls_, Aug 13 2004 %E A096594 a(17) from _Giovanni Resta_, Feb 19 2013