OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..450
EXAMPLE
a(1)=5 because 5!=120 has 3 (prime) digits.
MATHEMATICA
Select[ Select[ Range[2500], PrimeQ[ Floor[ Log[10, #! ] + 1]] & ], PrimeQ[ # ] & ]
Select[Prime[Range[400]], PrimeQ[IntegerLength[#!]]&] (* Harvey P. Dale, Mar 08 2018 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Sudipta Das (juitech(AT)vsnl.net), Feb 23 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Feb 28 2002
STATUS
approved