a(n) = (3*n+1)*(3*n+2).

Terms

a(0) =2a(1) =20a(2) =56a(3) =110a(4) =182a(5) =272a(6) =380a(7) =506a(8) =650a(9) =812a(10) =992a(11) =1190a(12) =1406a(13) =1640a(14) =1892a(15) =2162a(16) =2450a(17) =2756a(18) =3080a(19) =3422a(20) =3782a(21) =4160a(22) =4556a(23) =4970a(24) =5402a(25) =5852a(26) =6320a(27) =6806a(28) =7310a(29) =7832