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

1,1

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.

Links

Table of n, a(n) for n=1..12.

Formula

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

Prog

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

Crossrefs

Sequence in context: A035681 A195601 A352723 * A350970 A126788 A098789

Adjacent sequences: A222252 A222253 A222254 * A222256 A222257 A222258

Keyword

nonn

Author

M. F. Hasler, Mar 27 2013

Status

approved