%I #24 Mar 11 2015 23:52:42
%S 2,3,7,43,3263443
%N Primes in Sylvester's sequence A000058.
%C No more primes up to 21st recurrence step. - _Artur Jasinski_, Sep 20 2008
%C Andersen's page shows that A000058(30) is the first number whose primality is unknown. Thus if a(6) exists it has over 218 million decimal digits.
%H Jens Kruse Andersen, <a href="http://primerecords.dk/sylvester-factors.htm">Factorization of Sylvester's sequence</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SylvestersSequence.html">Sylvester's Sequence</a>
%t a = {}; k = 2; Do[k = k^2 - k + 1; If[PrimeQ[k], AppendTo[a, k]], {n, 1, 15}]; a (* _Artur Jasinski_, Sep 20 2008 *)
%Y Cf. A000058.
%K nonn
%O 1,1
%A _Eric W. Weisstein_