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

0,6

Comments

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

Links

Table of n, a(n) for n=0..7.

Example

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.

Sequence in context: A129616 A105006 A318788 * A071371 A052094 A256123

Adjacent sequences: A090871 A090872 A090873 * A090875 A090876 A090877

Keyword

nonn,hard,more

Author

Farideh Firoozbakht, Feb 06 2004

Extensions

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

a(7) from Kellen Shenton, Aug 27 2022

Status

approved