a(n) = 54*n^2 + 6*n.

Terms

a(0) =0a(1) =60a(2) =228a(3) =504a(4) =888a(5) =1380a(6) =1980a(7) =2688a(8) =3504a(9) =4428a(10) =5460a(11) =6600a(12) =7848a(13) =9204a(14) =10668a(15) =12240a(16) =13920a(17) =15708a(18) =17604a(19) =19608a(20) =21720a(21) =23940a(22) =26268a(23) =28704a(24) =31248a(25) =33900a(26) =36660a(27) =39528a(28) =42504a(29) =45588