A096178 Primes of the form primorial(p)/2+2.

3, 5, 17, 107, 15017, 3234846617, 100280245067, 3710369067407, 307444891294245707, 961380175077106319537, 139867498408927468089138080936033904837498617

Offset: 1

Author

Hugo Pfoertner, Jun 27 2004

Keywords

• nonn

Comments

Primes of the form A070826(n)+2.

Examples

			a(4) = 107 because 107 is a prime of the form primorial(7)/2 + 2 = A070826(4) + 2 = 2*3*5*7/2 + 2.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..18

Crossrefs

Cf. A070826, A096177 (primorial(p)/2+2 is prime), A096547 (primorial(p)/2-2 is prime), A067024 (smallest p+2 that has n distinct prime factors), A014545 (primorial primes), A087398.

Programs

PARI

for(n=1,30,p=prod(k=1,n,prime(k))/2+2;if(ispseudoprime(p),print1(p,", "))) \\ Hugo Pfoertner, Dec 26 2019

Formula

a(n) = A070826(A096177(n)) + 2. - Amiram Eldar, Dec 26 2019

Extensions

a(1) inserted by Amiram Eldar, Dec 26 2019