tetrahedral numbers

created by artemis entreri
(thing) by artemis entreri (1.1 y) (print)   (I like it!) Sun Feb 11 2001 at 6:11:17
Integers that can be expressed as a tetrahedral array in 3-space. Another charcterization is as the binomial coefficient C(n,4) (for n > 3 ).

An explicit formula for Tn in terms of n is:

Tn = n(n+1)(n+2)/6

--back to combinatorics--
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