A379694 Numbers k such that 4^k - prime(k) is prime.

1, 2, 3, 5, 9, 24, 49, 1466, 4588, 27804, 60126

Offset: 1

Author

Vincenzo Librandi, Dec 30 2024

Keywords

• nonn
• more

Comments

a(12) > 10^5. - Michael S. Branicky, Jan 02 2025

Examples

			2 in sequence because 4^2 - prime(2) = 16 - 3 = 13 (prime).
4 is not in sequence because 4^4 - prime(4) = 256 - 7 = 249 (not prime).
		

Crossrefs

Cf. A078583, A110066.

Programs

Magma

[n: n in [0..1500] | IsPrime(4^n-NthPrime(n))];

Mathematica

Do[If[PrimeQ[4^n-Prime[n]],Print[n]],{n,1,3*10^4}]

Extensions

a(11) from Michael S. Branicky, Jan 01 2025