A Figurate Number constructed by taking the th Tetrahedral Number and removing the th
Tetrahedral 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 tetrahedral numbers 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. Sequence
A005906/M5002
in ``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.

© 1996-9

1999-05-26