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A097521 Difference between F(n) = 2^(2^n)+1 and nextprime(F(n)) where F(n) is the n-th Fermat Number. 1
2, 2, 2, 6, 2, 14, 12, 50, 296, 74, 642, 980, 1760, 896, 2774, 118112, 44060, 5850 (list; graph; refs; listen; history; text; internal format)
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: A230940 A110512 A078020 * 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

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Last modified July 11 03:19 EDT 2020. Contains 335609 sequences. (Running on oeis4.)