A099440 Primes of the form A000295(k) = 2^k - k - 1.

11, 1013, 16369, 65519, 67108837, 1125899906842573, 72057594037927879, 1180591620717411303353, 83076749736557242056487941267521419

Offset: 1

Author

Hugo Pfoertner, Oct 18 2004

Keywords

• nonn

Comments

The next term a(10) = 2^2072-2073 has 624 decimal digits.

a(11) has 1882 decimal digits. - Vincenzo Librandi, Jul 18 2012

Examples

			a(2) = 1013 because A000295(A099439(2)) = 2^10 - 10 - 1 is prime.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..10

Crossrefs

Cf. A000295 2^n-n-1 (column 2 of the Eulerian numbers), A099439 2^n-n-1 is prime, A099441 2^n-n-1 is a semiprime, A099442 semiprimes in A000295.

Programs

Magma

[ a: n in [1..200] | IsPrime(a) where a is 2^n-n-1 ]; // Vincenzo Librandi, Jul 18 2012

Mathematica

Select[Table[2^n-n-1,{n,0,7000}],PrimeQ] (* Vincenzo Librandi, Jul 18 2012 *)