Centered tetrahedral number

In mathematics, a centered tetrahedral number is a centered figurate number that represents a tetrahedron. That is, it counts the dots in a three-dimensional dot pattern with a single dot surrounded by tetrahedral shells. The th centered tetrahedral number, starting at for a single dot, is:

The first such numbers are:

1, 5, 15, 35, 69, 121, 195, 295, 425, 589, 791, ...

References


Uses material from the Wikipedia article Centered tetrahedral number, released under the CC BY-SA 4.0 license.