Truncated Tetrahedral Number
A Figurate Number constructed by taking the 
th Tetrahedral Number and removing the 
thTetrahedral Number from each of the four corners,
The first few are 1, 16, 68, 180, 375, ... (Sloane's A005906). The Generating Function for the truncated tetrahedralnumbers is
References
Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 46-47, 1996. Sloane, N. J. A. SequenceA005906/M5002in ``An On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.
- Clebsch-Aronhold Notation
- Clebsch Diagonal Cubic
- Clebsch-Gordan Coefficient
- Clement Matrix
- Clenshaw Recurrence Formula
- Clifford Algebra
- Clifford's Circle Theorem
- Clifford's Curve Theorem
- Cliff Random Number Generator
- Clique
- Clique Number
- Clock Solitaire
- Closed Curve
- Closed Curve Problem
- Closed Disk
- Closed Form
- Closed Graph Theorem
- Closed Interval
- Closed Set
- Close Packing
- Closure
- Clothoid
- Clove Hitch
- Clump
- Cluster