A075896 Primes of the form 2^k - k^2.

7, 79, 431, 130783, 523927, 2251799813682647, 9007199254738183, 2417851639229258349405791, 9671406556917033397642519, 664613997892457936451903530140158127, 784637716923335095479473677900958302012794430558004278391

Offset: 1

Author

Zak Seidov, Oct 17 2002

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..20

Crossrefs

Primes in A024012.

Cf. A061119, A072180.

Programs

Magma

[a: n in [1..200] | IsPrime(a) where a is 2^n-n^2]; // Vincenzo Librandi, Dec 07 2011

Mathematica

Select[Table[2^n - n^2, {n, 500}], PrimeQ] (* Vincenzo Librandi, Dec 07 2011 *)

PARI

for(n=2,10^7,if(isprime(2^n-n^2),print1(2^n-n^2",")))

Formula

a(n) = A024012(A072180(n)). - Elmo R. Oliveira, Feb 18 2025

Extensions

More terms from Ralf Stephan, Mar 30 2003