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

2, 7, 549755813869, 2475880078570760549798248403

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..4.

Example

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

Mathematica

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

Prog

(Magma) [a: n in [0..500] | IsPrime(a) where a is 2*4^n - n];
(PARI)
for(n=0, 10^3, if(ispseudoprime(2^(2*n+1)-n), print1(2^(2*n+1)-n, ", "))) \\ Derek Orr, Aug 28 2014

Crossrefs

Cf. A100362, A241861.

Sequence in context: A153089 A077548 A050809 * A095217 A230915 A242922

Adjacent sequences: A246513 A246514 A246515 * A246517 A246518 A246519

Keyword

nonn

Author

Juri-Stepan Gerasimov, Aug 28 2014

Status

approved