A226281 Least number k such that 3^(2^i) + k is prime for i = 0,1,..,n-1.

2, 2, 2, 2, 58, 440, 18248, 2024098, 4263330280, 22836544460, 40728071843930

Offset: 1

Author

Robin Garcia, Jun 02 2013

Keywords

• nonn
• more

Comments

Generalized Fermat primes of the form b^(2^i) + k.

Examples

			a(5) = 58 because k = 58 is the minimal k such that  N = 3^(2^i) + k is prime for i = 0, 1, 2 ,3 ,4; N = 61, 67, 139, 6619, 43046779. But 3^(2^5) + 58 is divisible by 37 and three other primes.
		

Crossrefs

Cf. A129613, A225560.

Extensions

a(11) from Giovanni Resta, Jun 17 2013