Definition:Fermat Prime/Sequence

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Sequence of Fermat Primes

The sequence of Fermat primes begins:

\(\ds 2^{\paren {2^0} } + 1\) \(=\) \(\ds 3\)
\(\ds 2^{\paren {2^1} } + 1\) \(=\) \(\ds 5\)
\(\ds 2^{\paren {2^2} } + 1\) \(=\) \(\ds 17\)
\(\ds 2^{\paren {2^3} } + 1\) \(=\) \(\ds 257\)
\(\ds 2^{\paren {2^4} } + 1\) \(=\) \(\ds 65 \, 537\)

No other Fermat primes are known.

This sequence is A019434 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).


Sources