A246516 Primes of the form 2*4^n - n.

2, 7, 549755813869, 2475880078570760549798248403

Offset: 1

Author

Juri-Stepan Gerasimov, Aug 28 2014

Keywords

• nonn

Comments

a(5) and a(6) are 125 and 266 decimal digits long, respectively. - Derek Orr, Aug 28 2014

Examples

			2*4^0 - 0 = 2 is prime, thus 2 is a member of this sequence.
		

Crossrefs

Cf. A100362, A241861.

Programs

Magma

[a: n in [0..500] | IsPrime(a) where a is 2*4^n - n];

Mathematica

Select[Table[2^(2n + 1) - n, {n, 0, 127}], PrimeQ] (* Alonso del Arte, Sep 16 2014 *)

PARI

for(n=0,10^3,if(ispseudoprime(2^(2*n+1)-n),print1(2^(2*n+1)-n,", "))) \\ Derek Orr, Aug 28 2014