A088730 Numbers of the form p^p - 1, where p is a prime.

3, 26, 3124, 823542, 285311670610, 302875106592252, 827240261886336764176, 1978419655660313589123978, 20880467999847912034355032910566, 2567686153161211134561828214731016126483468

Offset: 1

Author

Cino Hilliard, Nov 23 2003

Keywords

• nonn

Comments

Sum of reciprocals = 0.3721161884983118696170302604..

Examples

			a(1) = 3 because the first prime is 2 and 2^2 - 1 = 3.
a(2) = 26 because the second prime is 3 and 3^3 - 1 = 26.
a(3) = 3124 because the fifth prime is 5 and 5^5 - 1 = 3124.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..77

Crossrefs

Cf. A051674, A088807, A125135 (factorizations).

Programs

Magma

[p^p-1: p in PrimesUpTo(20)]; // Vincenzo Librandi, Mar 27 2014

Mathematica

Table[Prime[n]^Prime[n] - 1, {n, 10}] (* Alonso del Arte, May 22 2013 *)
#^#-1&/@Prime[Range[10]] (* Harvey P. Dale, Jun 10 2013 *)

PARI

a(n)={my(p=prime(n)); p^p-1;} \\ Joerg Arndt, May 27 2013

Formula

a(n) = A051674(n) - 1. - R. J. Mathar, Jul 15 2007

Extensions

More terms from Ray Chandler, Feb 21 2004