Fermat-Lucas Number

A number of the form $2^n+1$ obtained by setting $x=1$ in a Fermat-Lucas Polynomial. The first few are 3, 5, 9, 17, 33, ... (Sloane's A000051).

See also Fermat Number (Lucas)

References

Sloane, N. J. A. Sequence A000051/M0717 in ``An On-Line Version of the Encyclopedia of Integer Sequences.'' http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S. The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.