A067367 Primes p such that the number of digits in p! is also prime.

5, 23, 29, 43, 89, 107, 139, 193, 199, 211, 229, 239, 313, 347, 419, 457, 587, 641, 661, 673, 701, 739, 863, 877, 1091, 1097, 1103, 1217, 1259, 1283, 1361, 1381, 1447, 1493, 1549, 1607, 1609, 1663, 1693, 1741, 1861, 1973, 1987, 2083, 2251, 2351, 2399, 2423

Offset: 1

Author

Sudipta Das (juitech(AT)vsnl.net), Feb 23 2002

Keywords

• nonn
• base

Examples

			a(1)=5 because 5!=120 has 3 (prime) digits.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..450

Crossrefs

Cf. A035065.

Programs

Mathematica

Select[ Select[ Range[2500], PrimeQ[ Floor[ Log[10, #! ] + 1]] & ], PrimeQ[ # ] & ]
Select[Prime[Range[400]],PrimeQ[IntegerLength[#!]]&] (* Harvey P. Dale, Mar 08 2018 *)

Extensions

Edited and extended by Robert G. Wilson v, Feb 28 2002