A090874 a(n) is the smallest number m such that m^2^k + (m+1)^2^k is prime for k=0..n.

1, 1, 1, 1, 1, 1806390369, 218327374070, 3697211121741701604

Offset: 0

Author

Farideh Firoozbakht, Feb 06 2004

Keywords

• nonn
• hard
• more

Comments

The first five terms of this sequence correspond to Fermat primes.

Examples

			a(5)=1806390369 because this is the smallest number m such that m^2^k + (m+1)^2^k is prime for k=0,1,2,3,4 and 5.
		

Crossrefs

Cf. A090872, A090873, A019434, A000215.

Extensions

a(6) found by Kellen Shenton added by Jeppe Stig Nielsen, Mar 28 2022

a(7) from Kellen Shenton, Aug 27 2022