18-gonal (or octadecagonal) numbers: a(n) = n*(8*n-7).

Terms

a(0) =0a(1) =1a(2) =18a(3) =51a(4) =100a(5) =165a(6) =246a(7) =343a(8) =456a(9) =585a(10) =730a(11) =891a(12) =1068a(13) =1261a(14) =1470a(15) =1695a(16) =1936a(17) =2193a(18) =2466a(19) =2755a(20) =3060a(21) =3381a(22) =3718a(23) =4071a(24) =4440a(25) =4825a(26) =5226a(27) =5643a(28) =6076a(29) =6525