Centered tetrahedral number
Total no. of terms | Infinity |
---|---|
Subsequence of | Polyhedral numbers |
Formula | |
First terms | 1, 5, 15, 35, 69, 121, 195 |
OEIS index |
|
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.[1] The th centered tetrahedral number, starting at for a single dot, is:[2][3]
The first such numbers are:[1][2]
1, 5, 15, 35, 69, 121, 195, 295, 425, 589, 791, ...
References
[edit]- ^ a b Deza, E.; Deza, M. (2012). Figurate Numbers. Singapore: World Scientific Publishing. pp. 126–128. ISBN 978-981-4355-48-3.
- ^ a b Sloane, N. J. A. (ed.). "Sequence A005894 (Centered tetrahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Deza numbers the centered tetrahedral numbers at for a single dot, leading to a different formula.