Twice 11-gonal numbers: a(n) = n*(9*n-7).

Terms

a(0) =0a(1) =2a(2) =22a(3) =60a(4) =116a(5) =190a(6) =282a(7) =392a(8) =520a(9) =666a(10) =830a(11) =1012a(12) =1212a(13) =1430a(14) =1666a(15) =1920a(16) =2192a(17) =2482a(18) =2790a(19) =3116a(20) =3460a(21) =3822a(22) =4202a(23) =4600a(24) =5016a(25) =5450a(26) =5902a(27) =6372a(28) =6860a(29) =7366