| Total no. of terms | Infinity |
|---|---|
| Subsequence of | Polyhedral numbers |
| Formula | |
| First terms | 1, 5, 15, 35, 69, 121, 195 |
| OEIS index |
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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.
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Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction