Octagonal numbers are figurate numbers based on an 8-sided polygon, given by \(O_k = k(3k-2)\) for \(k \geq 1\). First terms: 1, 8, 21, 40, 65, 96, 133, 176, 225, 280.
Term
Octagonal
Figurate numbers k(3k−2) (1, 8, 21, 40, 65, 96, 133, 176, …).
27 numbers tagged.