Hex Pyramidal Number
A Figurate Number which is equal to the Cubic Number 
. The first few are 1, 8, 27, 64, ...(Sloane's A000578).
References
Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 42-44, 1996. Sloane, N. J. A. SequenceA000578/M4499in ``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.
- Lattice Graph
- Lattice Groups
- Lattice Path
- Lattice Point
- Lattice Reduction
- Lattice Sum
- Lattice Theory
- Latus Rectum
- Laurent Polynomial
- Laurent Series
- Law
- Law of Anomalous Numbers
- Law of Cancellation
- Law of Cosines
- Law of Large Numbers
- Law of Sines
- Law of Small Numbers
- Law of Tangents
- Law of Truly Large Numbers
- Lax-Milgram Theorem
- Lax Pair
- Layer
- Leading Digit Phenomenon
- Leading Order Analysis
- Leaf (Foliation)