a(n) = n*(15*n^2 - 15*n + 4).

Terms

a(0) =0a(1) =4a(2) =68a(3) =282a(4) =736a(5) =1520a(6) =2724a(7) =4438a(8) =6752a(9) =9756a(10) =13540a(11) =18194a(12) =23808a(13) =30472a(14) =38276a(15) =47310a(16) =57664a(17) =69428a(18) =82692a(19) =97546a(20) =114080a(21) =132384a(22) =152548a(23) =174662a(24) =198816a(25) =225100a(26) =253604a(27) =284418a(28) =317632a(29) =353336