Global InformationOctagonal number information
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An octagonal number is a figurate number that gives the number of points in a certain octagonal arrangement. The octagonal number for n is given by the formula 3n2 − 2n, with n > 0. The first few octagonal numbers are
- 1, 8, 21, 40, 65, 96, 133, 176, 225, 280, 341, 408, 481, 560, 645, 736, 833, 936 (sequence A000567 in the OEIS)
The octagonal number for n can also be calculated by adding the square of n to twice the (n − 1)th pronic number.
Octagonal numbers consistently alternate parity.
Octagonal numbers are occasionally referred to as "star numbers," though that term is more commonly used to refer to centered dodecagonal numbers.[1]
- ^ Deza, Elena; Deza, Michel (2012), Figurate Numbers, World Scientific, p. 57, ISBN 9789814355483.