A057909 Numbers k such that 4^k + k is prime.

1, 3, 9, 15, 37, 85, 133, 225, 1233, 12793, 108889

Offset: 1

Author

Robert G. Wilson v, Nov 16 2000

Keywords

• nonn
• more

Comments

a(11) > 20000. - Jinyuan Wang, Feb 01 2020

Crossrefs

Cf. A052007, A057900.

Cf. A158879 (4^n + n).

Programs

Mathematica

Do[ If[ PrimeQ[ 4^n + n ], Print[ n ] ], {n, 0, 3000} ]

PARI

is(n)=ispseudoprime(4^n+n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(10) from Jinyuan Wang, Feb 01 2020

a(11) from Hugo Pfoertner, Mar 02 2024