a(n) = 4*n^3 + 4*n.

Terms

a(0) =0a(1) =8a(2) =40a(3) =120a(4) =272a(5) =520a(6) =888a(7) =1400a(8) =2080a(9) =2952a(10) =4040a(11) =5368a(12) =6960a(13) =8840a(14) =11032a(15) =13560a(16) =16448a(17) =19720a(18) =23400a(19) =27512a(20) =32080a(21) =37128a(22) =42680a(23) =48760a(24) =55392a(25) =62600a(26) =70408a(27) =78840a(28) =87920a(29) =97672