A222255 Primes of the form n!/n# + 1, where n#=A034386(n) (primorial), listed with repetition.

2, 2, 2, 2, 5, 5, 193, 2903041, 250822656001, 1807729046323200001, 1472038679443987759104000001, 21817028147643299474152432146548259236610048000000000001

Offset: 1

Author

M. F. Hasler, Mar 27 2013

Keywords

• nonn

Comments

For each n >= 0, if n!/n#+1 is prime, then this prime is listed here: This explains the repetitions.

The next term is already 126 digits long.

Programs

PARI

for(n=0,99,ispseudoprime(a=n!/prod(k=1,primepi(n),prime(k))+1)&print1(a","))

Formula

a(n) = A049614(A140294(n))+1, where A049614 = A000142/A034386.