Stella octangula number

124 magnetic balls arranged into the shape of a stella octangula

In mathematics, a stella octangula number is a figurate number based on the stella octangula, of the form n(2n2 − 1).[1][2]

The sequence of stella octangula numbers is

0, 1, 14, 51, 124, 245, 426, 679, 1016, 1449, 1990, ... (sequence A007588 in the OEIS)[1]

Only two of these numbers are square.

  1. ^ a b Sloane, N. J. A. (ed.), "Sequence A007588 (Stella octangula numbers: n*(2*n^2 - 1))", The On-Line Encyclopedia of Integer Sequences, OEIS Foundation.
  2. ^ Conway, John; Guy, Richard (1996), The Book of Numbers, Springer, p. 51, ISBN 978-0-387-97993-9.