A262972 Numbers k such that 4^k + 33 is prime.

1, 3, 6, 7, 10, 15, 30, 34, 54, 58, 103, 105, 205, 223, 279, 741, 2098, 3523, 9210, 37674, 89895, 101509, 217123

Offset: 1

Author

Robert Price, Oct 05 2015

Keywords

• nonn
• more

Comments

Contains exactly the halved even terms of A247953.

The next terms are > 2*10^5.

Examples

			For k = 30, 4^30 + 33 = 1152921504606847009 is prime.
		

Crossrefs

Cf. A247953, A253772 (similar sequence).

Programs

Magma

[n: n in [0..700] | IsPrime(4^n+33)]; // Vincenzo Librandi, Oct 06 2015

Mathematica

Select[Range[0, 250000], PrimeQ[4^# + 33] &]

PARI

for(n=1, 1e3, if(isprime(4^n+33), print1(n", "))) \\ Altug Alkan, Oct 06 2015

Extensions

a(23) derived from A247953 by Elmo R. Oliveira, Nov 28 2023