A154525 Primes p such that lcm(1,2,3,...,p-2,p-1,p) + 1 is prime.

2, 3, 5, 7, 19, 31, 47, 89, 127, 139, 2251, 3271, 4253, 4373, 4549, 5449, 13331, 37123, 55291

Offset: 1

Author

Lekraj Beedassy, Jan 11 2009

Keywords

• nonn

Crossrefs

Cf. A056604, A154524, A154526.

Programs

Mathematica

Select[Range[1000], PrimeQ[#] && PrimeQ[LCM@@Range[#]+1] &] (* Amiram Eldar, Nov 21 2018 *)

PARI

isok(p) = isprime(p) && (isprime(lcm(vector(p, i, i)) + 1)); \\ Michel Marcus, Oct 26 2013, Feb 25 2014

Formula

A049537 INTERSECT A000040. - Ray Chandler, Jan 16 2009

Extensions

a(1)=2 inserted and a(8)-a(18) from Ray Chandler, Jan 16 2009

a(19) from Daniel Suteu, Nov 21 2018