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 A109993 #11 Dec 15 2017 17:36:56 %S A109993 2,14,16,18,26,30,36,42,62,132,242,294,302,666,816,824,998,1218,1472, %T A109993 2522,3098,4148,6404,8102,25656,26490,56702,76442 %N A109993 Numbers n such that 65537 * 2^n - 1 is prime. %C A109993 Note that 65537 = 2^16 + 1 is the largest known Fermat prime. All terms have been proved prime. Proof for the largest: PFGW Version 1.2.0 for Windows [FFT v23.8] Primality testing 65537*2^76442-1 [N+1, Brillhart-Lehmer-Selfridge] Running N+1 test using discriminant 3, base 1+sqrt(3) Calling Brillhart-Lehmer-Selfridge with factored part 99.98% 65537*2^76442-1 is prime! (101.6260s+0.0044s) %C A109993 No more terms up to 92000. %t A109993 Select[Range[1, 1000], PrimeQ[65537*2^# - 1] &] (* _Julien Kluge_, Jul 08 2016 *) %o A109993 (PARI) is(n)=ispseudoprime(65537*2^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A109993 Cf. A112245. %K A109993 more,nonn %O A109993 1,1 %A A109993 _Jason Earls_, Sep 01 2005