%I #15 Aug 15 2015 10:07:14
%S 1,309,381600854690147056244358827361
%N Number of decimal digits in Fermat(10^n).
%C Next term a(3) has 301 digits.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/FermatNumber.html">Fermat Number</a>
%t Block[{$MaxExtraPrecision = Infinity}, Table[1 + Floor[2^10^n Log[10, 2]], {n, 0, 2}]]
%Y Subsequence of A057755. - _Arkadiusz Wesolowski_, Jun 30 2011
%Y Cf. A000021.
%K nonn,base,bref
%O 0,2
%A _Eric W. Weisstein_, Nov 30 2005