A073309 Primes of the form k! + k + 1.

2, 3, 5, 29, 727, 3628811, 80658175170943878571660636856403766975289505440883277824000000000053

Offset: 1

Author

Rick L. Shepherd, Jul 24 2002

Keywords

• nonn

Comments

a(6) = 3628811 and a(7), a 68-digit number, have been certified prime with Primo.

Examples

			a(4) = 6! + 6 + 1 = 727, a prime, so 727 is in this sequence (6 = A073308(4)).
		

Crossrefs

Cf. A073308 (corresponding n), A100858.

Programs

Mathematica

f[n_]:=n!+n+1; lst={};Do[p=f[n];If[PrimeQ[p],AppendTo[lst,p]],{n,0,2*5!}];lst (* Vladimir Joseph Stephan Orlovsky, Jul 02 2009 *)

PARI

for(n=0,1960,p=n!+n+1; if(isprime(p),print1(p,",")))

Formula

a(n) = A073308(n)! + A073308(n) + 1.