Trinomial Triangle
The Number Triangle obtained by starting with a row containing a single ``1'' and the next row containing three 1s andthen letting subsequent row elements be computed by summing the elements above to the left, directly above, and above to the right:
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th row can also be obtained by expanding 
and taking coefficients: |  |  | |
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and so on.See also Pascal's Triangle
References
Sloane, N. J. A. Sequence A027907in ``The On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html.
- Rectifying Latitude
- Rectifying Plane
- 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