a(n) = 18n^3 + 6n^2.

Terms

a(0) =0a(1) =24a(2) =168a(3) =540a(4) =1248a(5) =2400a(6) =4104a(7) =6468a(8) =9600a(9) =13608a(10) =18600a(11) =24684a(12) =31968a(13) =40560a(14) =50568a(15) =62100a(16) =75264a(17) =90168a(18) =106920a(19) =125628a(20) =146400a(21) =169344a(22) =194568a(23) =222180a(24) =252288a(25) =285000a(26) =320424a(27) =358668a(28) =399840a(29) =444048