Hexagonal Pyramidal Number
A Pyramidal Number of the form 
, The first few are 1, 7, 22, 50, 95, ... (Sloane's A002412). TheGenerating Function of the hexagonal pyramidal numbers is
References
Sloane, N. J. A. SequenceA002412/M4374in ``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.
- Spider Lines
- Spiegeldrieck
- Spieker Center
- Spieker Circle
- Spigot Algorithm
- Spijker's Lemma
- Spindle Cyclide
- Spindle Torus
- Spinode
- Spinor
- Spiral
- Spiral Point
- Spira Mirabilis
- Spiric Section
- Spirograph
- Spirolateral
- Spline
- Splitting
- Splitting Algorithm
- Sponge
- Sporadic Group
- Sports
- Sprague-Grundy Function
- Sprague-Grundy Number
- Sprague-Grundy Value