|
|
A176038
|
|
Primes of the form n!*(n+1)! - 1 or n!*(n+1)! + 1.
|
|
1
|
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Primes of the form A010790(k)-1 or A010790(k)+1. This is the 2nd sequence in the supersequence whose first member is factorial primes, A002981 UNION A002982. No more through 20!*(20+1)! + 1.
a(9) has already 225 digits. The terms are generated by n= 0,1,2,2,4,5,14,32,76,166... [From R. J. Mathar, Aug 31 2010]
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
a(6) = 86399 because 5!*(5+1)! - 1 = 86399 is prime. a(7) = 114000816848279961600001 because 14!*(14+1)! + 1 = 114000816848279961600001 is prime.
|
|
CROSSREFS
|
|
|
KEYWORD
|
more,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|