A097521 Difference between F(n) = 2^(2^n)+1 and nextprime(F(n)) where F(n) is the n-th Fermat Number.

2, 2, 2, 6, 2, 14, 12, 50, 296, 74, 642, 980, 1760, 896, 2774, 118112, 44060, 5850

Offset

0,1

Comments

In the Name, nextprime means A151800, not A007918. - Jeppe Stig Nielsen, Nov 18 2019

a(n) = A129786(n)-1 except in the rare case that F(n) is a prime. - Jeppe Stig Nielsen, Nov 18 2019

Links

Table of n, a(n) for n=0..17.

Formula

a(n) = A013632(A000215(n)). - Michel Marcus, Nov 18 2019

Example

F(5) = 4294967297. Nextprime(F(5)) = 4294967311.
4294967311 - 4294967297 = 14 the 6th entry in the table.

Prog

(PARI) for(n=0, +oo, print1(nextprime(2^(2^n)+2)-(2^(2^n)+1), ", ")) \\ Jeppe Stig Nielsen, Nov 18 2019

Crossrefs

Cf. A000215, A013632, A151800, A129786.

Sequence in context: A110512 A078020 A339091 * A081668 A126615 A158524

Adjacent sequences: A097518 A097519 A097520 * A097522 A097523 A097524

Keyword

nonn,more

Author

Cino Hilliard, Aug 27 2004

Extensions

More terms with the help of A129786 from Jeppe Stig Nielsen, Nov 18 2019

Status

approved