%I A035065
%S A035065 4,5,6,8,10,14,15,20,23,27,29,33,35,39,43,51,58,68,70,84,86,89,90,95,
%T A035065 104,107,110,111,116,117,119,120,133,134,136,139,147,150,158,159,170,
%U A035065 183,193,199,206,211,224,229,235,239,244,249,254,270,279,282,291,299
%N A035065 n! has a prime number of digits.
%H A035065 <a href="Sindx_Fa.html#factorial">Index entries for sequences related 
               to factorial numbers</a>
%e A035065 a(1)=4 because 4! = 24 has 2 ( prime ) digits.
%e A035065 23! = 25852016738884976640000 has exactly 23 digits !
%t A035065 Select[ Range[300], PrimeQ[ Floor[ Log[10, #! ] + 1]] & ]
%Y A035065 Cf. A000142, A035066, A067367.
%Y A035065 Sequence in context: A087947 A053427 A037354 this_sequence A035067 A027698 
               A047313
%Y A035065 Adjacent sequences: A035062 A035063 A035064 this_sequence A035066 A035067 
               A035068
%K A035065 nonn,base
%O A035065 0,1
%A A035065 Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 15 1998.