4 times octagonal numbers: a(n) = 4*n*(3*n-2).

Terms

a(0) =0a(1) =4a(2) =32a(3) =84a(4) =160a(5) =260a(6) =384a(7) =532a(8) =704a(9) =900a(10) =1120a(11) =1364a(12) =1632a(13) =1924a(14) =2240a(15) =2580a(16) =2944a(17) =3332a(18) =3744a(19) =4180a(20) =4640a(21) =5124a(22) =5632a(23) =6164a(24) =6720a(25) =7300a(26) =7904a(27) =8532a(28) =9184a(29) =9860