Dodecahedral number

A dodecahedral number is a figurate number that represents a dodecahedron. The nth dodecahedral number is given by the formula

${\displaystyle {n(3n-1)(3n-2) \over 2}={3n \choose 3}}$

The first such numbers are 0, 1, 20, 84, 220, 455, 816, 1330, 2024, 2925, 4060, 5456, 7140, 9139, 11480, … (sequence A006566 in the OEIS).