A049536 Primes of the form lcm(1, ..., n) + 1 = A003418(n) + 1.

2, 3, 7, 13, 61, 421, 2521, 232792561, 26771144401, 72201776446801, 442720643463713815201, 718766754945489455304472257065075294401, 6676878045498705789701874602220118271269436344024536001

Offset: 1

Author

Labos Elemer

Keywords

• nonn

Examples

			Lcm(9) + 1 = lcm(10) + 1 = 2521, a prime.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..16

Crossrefs

Subsequence of A070858.

Cf. A003418, A049537, A057824.

Programs

Mathematica

Select[Table[LCM@@Range[n]+1,{n,150}],PrimeQ]//Union (* Harvey P. Dale, May 31 2017 *)

PARI

N=1; print1(2); for(n=1,1e3, if(isprimepower(n,&p), N*=p; if(isprime(N+1), print1(", "N+1)))) \\ Charles R Greathouse IV, Nov 18 2015