A081713 n! - n# - 1 is prime, where n# is the primorial function.

4, 5, 20, 92, 106, 266, 308, 343, 583, 597, 903, 1021, 1239, 1314, 2458, 6160, 9627, 10649

Offset

1,1

Comments

Some of the larger entries may only correspond to probable primes.

Links

Table of n, a(n) for n=1..18.

Mike Oakes, Primo-factorials.

Mike Oakes, Primo-factorials, message 12028 in primenumbers Yahoo group, Apr 3, 2003. [Cached copy]

Joe McLean, Interesting Sources of Probable Primes.

Example

a(1)=4 because 4!-4#-1=17 is prime

Crossrefs

Cf. A081710, A081711, A081712.

Sequence in context: A119283 A151499 A057781 * A344950 A344151 A120697

Adjacent sequences: A081710 A081711 A081712 * A081714 A081715 A081716

Keyword

nonn,more,hard

Author

Mike Oakes, Apr 04 2003

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

Status

approved