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 A067367 Primes p such that the number of digits in p! is also prime. 2

%I

%S 5,23,29,43,89,107,139,193,199,211,229,239,313,347,419,457,587,641,

%T 661,673,701,739,863,877,1091,1097,1103,1217,1259,1283,1361,1381,1447,

%U 1493,1549,1607,1609,1663,1693,1741,1861,1973,1987,2083,2251,2351,2399,2423

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

%H Vincenzo Librandi, <a href="/A067367/b067367.txt">Table of n, a(n) for n = 1..450</a>

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

%t Select[ Select[ Range[2500], PrimeQ[ Floor[ Log[10, #! ] + 1]] & ], PrimeQ[ # ] & ]

%t Select[Prime[Range[400]],PrimeQ[IntegerLength[#!]]&] (* _Harvey P. Dale_, Mar 08 2018 *)

%Y Cf. A035065.

%K nonn,base

%O 1,1

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

%E Edited and extended by _Robert G. Wilson v_, Feb 28 2002

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Last modified June 20 09:12 EDT 2019. Contains 324234 sequences. (Running on oeis4.)