A050528 Primes of the form 9*2^n+1.

19, 37, 73, 577, 1153, 18433, 147457, 1179649, 77309411329, 39582418599937, 79164837199873, 83010348331692982273, 332041393326771929089, 1328165573307087716353, 21760664753063325144711169, 196002643346460554954903773880698489798657

Offset: 1

Author

N. J. A. Sloane, Dec 29 1999

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..25
• Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Crossrefs

For more terms see A002256.

Programs

Magma

[a: n in [0..150] | IsPrime(a) where a is (9*2^n+1) ]; // Vincenzo Librandi, Aug 09 2014

Maple

A050528:=n->`if`(isprime(9*2^n+1),9*2^n+1,NULL): seq(A050528(n), n=1..200); # Wesley Ivan Hurt, Aug 09 2014

Mathematica

Select[9*2^Range[150]+1,PrimeQ] (* Harvey P. Dale, Aug 08 2014 *)