Hansen Number
A number 
for which a shortest chain exists which is a Hansen Chain is called a Hansen number.
References
Guy, R. K. Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 111-112, 1994.
- Fifteen Theorem
- Figurate Number
- Figurate Number Triangle
- Figure Eight Knot
- Figure Eight Surface
- Figure-of-Eight Knot
- Figures
- Filon's Integration Formula
- Filter
- Fine's Equation
- Finite
- Finite Difference
- Finite Field
- Finite Game
- Finite Group
- Finite Group D3
- Finite Group D4
- Finite Group e
- Finite Group Q8
- Finite Group Z2
- Finite Group Z2Z2
- Finite Group Z2Z2Z2
- Finite Group Z2Z4
- Finite Group Z3
- Finite Group Z4