a(n) = 12*n^3 + 9*n^2 + 2*n.

Terms

a(0) =0a(1) =23a(2) =136a(3) =411a(4) =920a(5) =1735a(6) =2928a(7) =4571a(8) =6736a(9) =9495a(10) =12920a(11) =17083a(12) =22056a(13) =27911a(14) =34720a(15) =42555a(16) =51488a(17) =61591a(18) =72936a(19) =85595a(20) =99640a(21) =115143a(22) =132176a(23) =150811a(24) =171120a(25) =193175a(26) =217048a(27) =242811a(28) =270536a(29) =300295