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

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

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..7.

Formula

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

Example

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

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 *)

Prog

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

Crossrefs

Cf. A073308 (corresponding n), A100858.

Sequence in context: A279189 A107451 A093490 * A226124 A110389 A083388

Adjacent sequences: A073306 A073307 A073308 * A073310 A073311 A073312

Keyword

nonn

Author

Rick L. Shepherd, Jul 24 2002

Status

approved