q-Pi
The q-Analog of Pi 
can be defined by taking 
in theq-Factorial
giving
where
is the q-Sine. Gosper has developed an iterative algorithm for computing 
based on the algebraic Recurrence Relation
- Recurrence Sequence
- Recurring Digital Invariant
- Recursion
- Recursive Function
- Recursive Monotone Stable Quadrature
- Red-Black Tree
- Red Net
- Reduced Amicable Pair
- Reduced Fraction
- Reduced Latitude
- Reducible Crossing
- Reducible Matrix
- Reducible Representation
- Reduction of Order
- Reduction Theorem
- Redundancy
- Reeb Foliation
- Reef Knot
- Re-Entrant Circuit
- Refinement
- Reflection
- Reflection Property
- Reflection Relation
- Reflexible
- Reflexible Map