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

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

Offset

1,1

Comments

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

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

Links

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

Example

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

Mathematica

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

Prog

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

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.

Sequence in context: A303786 A015511 A065050 * A073903 A069710 A046187

Adjacent sequences: A099437 A099438 A099439 * A099441 A099442 A099443

Keyword

nonn

Author

Hugo Pfoertner, Oct 18 2004

Status

approved