Self-Descriptive Number
A 10-Digit number satisfying the following property. Number the Digits 0 to 9, and let Digit 
be the number of s in the number. There is exactly one such number: 6210001000.
References
Pickover, C. A. ``Chaos in Ontario.'' Ch. 28 in Keys to Infinity. New York: Wiley, pp. 217-219, 1995.
- Feuerbach Circle
- Feuerbach Point
- Feuerbach's Conic Theorem
- Feuerbach's Theorem
- Feynman Point
- FFT
- Fiber
- Fiber Bundle
- Fiber Space
- Fibonacci Dual Theorem
- Fibonacci Hyperbolic Cosine
- Fibonacci Hyperbolic Cotangent
- Fibonacci Hyperbolic Sine
- Fibonacci Hyperbolic Tangent
- Fibonacci Identity
- Fibonacci Matrix
- Fibonacci n-Step Number
- Fibonacci Number
- Fibonacci Polynomial
- Fibonacci Pseudoprime
- Fibonacci Q-Matrix
- Fibonacci Sequence
- Fibration
- Field
- Field Axioms