A261639 Values of n such that prime(n+1)!/prime(n) + 1 is a prime number.

2, 3, 4, 5, 19, 110

Offset

1,1

Comments

a(1) = 2, a(2) = 3, a(3) = 4, a(4) = 5. It can be seen as a nice consecutiveness on sequence for first four items. Another point is that sequence of prime(n+1)! / prime(n) is observed in A260754.

a(7) > 2300. - Giovanni Resta, Aug 28 2015

Links

Table of n, a(n) for n=1..6.

Example

For n=2 the (prime(n+1)! / prime(n)) + 1 = 41. 41 is prime.

Prog

(PARI) for(n=1, 1e3, if(isprime(k=((prime(n+1)!/prime(n))+1)), print1(n", ")))

Crossrefs

Cf. A260754.

Sequence in context: A295317 A165646 A377072 * A333993 A362064 A342617

Adjacent sequences: A261636 A261637 A261638 * A261640 A261641 A261642

Keyword

nonn,more

Author

Altug Alkan, Aug 27 2015

Status

approved