a(n) = n^5 - n.

Terms

a(0) =0a(1) =0a(2) =30a(3) =240a(4) =1020a(5) =3120a(6) =7770a(7) =16800a(8) =32760a(9) =59040a(10) =99990a(11) =161040a(12) =248820a(13) =371280a(14) =537810a(15) =759360a(16) =1048560a(17) =1419840a(18) =1889550a(19) =2476080a(20) =3199980a(21) =4084080a(22) =5153610a(23) =6436320a(24) =7962600a(25) =9765600a(26) =11881350a(27) =14348880a(28) =17210340a(29) =20511120