A092967 Largest prime of the form a squarefree number + 1 where the prime divisors of the squarefree number are < n.

2, 3, 7, 7, 31, 31, 211, 211, 211, 211, 2311, 2311, 6007, 6007, 6007, 6007, 102103, 102103, 3233231, 3233231, 3233231, 3233231, 17160991

Offset: 1

Author

Amarnath Murthy, Mar 26 2004

Keywords

• nonn

Comments

Conjecture: a(n)-1 has prime(n)-1 divisors. Subsidiary sequence: Number of primes of the form 2*p*q*r*...+1 where p, q, r, etc. are distinct odd primes < n.

Examples

			a(13) = 6007 = 2*3*7*11*13 + 1, as 2*5*7*11*13 + 1, etc. are composite.
		

Crossrefs

Cf. A092965, A060957.

Programs

Mathematica

<Ryan Propper, Aug 13 2005 *)

Extensions

More terms from Ryan Propper, Aug 13 2005