A069460 Greatest prime factor of prime(n)^n - 1.

2, 31, 5, 3221, 157, 25646167, 3833, 7792003, 732541, 150332843, 144061, 17615988547, 6177695707, 461017351, 31129845205681, 361353204962363828785531, 903870199, 751410597400064602523400427092397, 25058741, 153436090543, 1750258119644519

Offset: 2

Author

Reinhard Zumkeller, Mar 24 2002

Keywords

• nonn

Examples

			A000040(9)^9 - 1 = 23^9 - 1 = 1801152661462 = 2*7*11*19*79*7792003, therefore a(9) = 7792003.
		

Links

• Hugo Pfoertner and Amiram Eldar, Table of n, a(n) for n = 2..96 (terms 2..50 from Hugo Pfoertner)
• Dario Alpern, Factorization using the Elliptic Curve Method.
• FactorDB, Status of 509^97-1.

Crossrefs

Cf. A006530, A069459, A069463.

Programs

Mathematica

Table[FactorInteger[Prime[n]^n-1][[-1,1]],{n,2,30}] (* Harvey P. Dale, May 19 2019 *)

Formula

a(n) = A006530(A069459(n)).

Extensions

More terms from Hugo Pfoertner, May 18 2004

Undefined a(1) removed by Hugo Pfoertner, Jul 22 2019