Brahmagupta's Problem
Solve the Pell Equation
in Integers. The smallest solution is
, 
.See also Diophantine Equation, Pell Equation- Algorithmic Complexity
- Alhazen's Billiard Problem
- Alhazen's Problem
- Aliasing
- Aliquant Divisor
- Aliquot Cycle
- Aliquot Divisor
- Aliquot Sequence
- Alladi-Grinstead Constant
- Allais Paradox
- Allegory
- Allometric
- All-Poles Model
- Almost All
- Almost Alternating Knot
- Almost Alternating Link
- Almost Everywhere
- Almost Integer
- Almost Perfect Number
- Almost Prime
- Alpha
- Alphabet
- Alpha Function
- Alphamagic Square
- Alphametic