A108180 Numbers k such that k^k * (k!/k#) + 1 is prime, where k# = primorial numbers (A034386).

1, 2, 8, 20, 23, 55, 57, 58, 181, 741, 939

Offset

1,2

Comments

k!/k# is known as n compositorial. All values have been proved prime. No more terms up to 3200.

a(12) > 10000. - Michael S. Branicky, May 16 2025

Links

Table of n, a(n) for n=1..11.

Crossrefs

Sequence in context: A030097 A136904 A043002 * A233571 A192153 A190640

Adjacent sequences: A108177 A108178 A108179 * A108181 A108182 A108183

Keyword

nonn,hard,more

Author

Jason Earls, Jul 24 2005

Status

approved