Selfridge-Hurwitz Residue
Let the Residue from Pépin's Theorem be
where
is a Fermat Number. Selfridge and Hurwitz use
A nonvanishing
indicates that is Composite for 
.See also Fermat Number, Pépin's Theorem
References
Crandall, R.; Doenias, J.; Norrie, C.; and Young, J. ``The Twenty-Second Fermat Number is Composite.'' Math. Comput. 64, 863-868, 1995.
- Parabolic Horn Cyclide
- Parabolic Partial Differential Equation
- Parabolic Point
- Parabolic Ring Cyclide
- Parabolic Rotation
- Parabolic Segment
- Parabolic Spindle Cyclide
- Parabolic Spiral
- Parabolic Umbilic Catastrophe
- Paraboloid
- Paraboloidal Coordinates
- Paraboloid Geodesic
- Paracompact Space
- Paracycle
- Paradox
- Paradromic Rings
- Paragyrate Diminished Rhombicosidodecahedron
- Parallel
- Parallel Axiom
- Parallel Class
- Parallel Curve
- Parallelepiped
- Parallelism
- Parallelizable
- Parallelogram