A051438 a(n) = prime(2^n - 1).

2, 5, 17, 47, 127, 307, 709, 1613, 3659, 8147, 17851, 38867, 84011, 180497, 386083, 821603, 1742527, 3681113, 7754017, 16290041, 34136021, 71378551, 148948133, 310248233, 645155191, 1339484149, 2777105117, 5750079043, 11891268397, 24563311217, 50685770143

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..78 (calculated using the b-file at A033844; terms 1..57 from Hugo Pfoertner)

Crossrefs

Cf. A000040, A000225, A033844, A018249, A051440, A051439, A151799.

Programs

Mathematica

Prime[2^Range[34] - 1] (* Vladimir Joseph Stephan Orlovsky, Jul 19 2011 *)

PARI

a(n)=prime(2^n-1) \\ Charles R Greathouse IV, Sep 28 2015

Formula

a(n) = A181363(2^n - 1). - Reinhard Zumkeller, Oct 16 2010

a(n) = A000040(A000225(n)). - Michel Marcus, Nov 28 2017

a(n) = A151799(A033844(n)). - Amiram Eldar, Jun 30 2024

Extensions

More terms from Michael Lugo (mlugo(AT)thelabelguy.com), Dec 22 1999