Decagonal numbers are figurate numbers based on a 10-sided polygon, given by \(D_k = k(4k-3)\) for \(k \geq 1\). First terms: 1, 10, 27, 52, 85, 126, 175, 232, 297, 370. Every decagonal number ends in 0, 1, 2, 5, 6, or 7 in base 10.
Term
Decagonal
Figurate numbers k(4k−3) (1, 10, 27, 52, 85, 126, 175, 232, …).
22 numbers tagged.