Dodecahedral numbers: a(n) = n*(3*n - 1)*(3*n - 2)/2.

Terms

a(0) =0a(1) =1a(2) =20a(3) =84a(4) =220a(5) =455a(6) =816a(7) =1330a(8) =2024a(9) =2925a(10) =4060a(11) =5456a(12) =7140a(13) =9139a(14) =11480a(15) =14190a(16) =17296a(17) =20825a(18) =24804a(19) =29260a(20) =34220a(21) =39711a(22) =45760a(23) =52394a(24) =59640a(25) =67525a(26) =76076a(27) =85320a(28) =95284a(29) =105995