A081711 Numbers k such that k! + k# - 1 is prime, where k# is the primorial function.

2, 3, 4, 5, 8, 17, 23, 26, 35, 47, 82, 100, 147, 183, 271, 492, 708, 1116, 1538, 2491, 4207, 4468

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..22.

Mike Oakes, Primo-factorials.

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

Example

a(1)=2 because 2!+2#-1=3 is prime

Crossrefs

Cf. A081710, A081712, A081713.

Sequence in context: A281303 A264011 A337280 * A055638 A375285 A057657

Adjacent sequences: A081708 A081709 A081710 * A081712 A081713 A081714

Keyword

nonn,more,hard

Author

Mike Oakes, Apr 04 2003

Extensions

Offset and ordering corrected by Sean A. Irvine, Sep 18 2023

Status

approved