a(n) = T(n^3) - T(n), where T() are the triangular numbers (A000217).

Terms

a(0) =0a(1) =0a(2) =33a(3) =372a(4) =2070a(5) =7860a(6) =23415a(7) =58968a(8) =131292a(9) =266040a(10) =500445a(11) =886380a(12) =1493778a(13) =2414412a(14) =3766035a(15) =5696880a(16) =8390520a(17) =12071088a(18) =17008857a(19) =23526180a(20) =32003790a(21) =42887460a(22) =56695023a(23) =74023752a(24) =95558100a(25) =122077800a(26) =154466325a(27) =193719708a(28) =240955722a(29) =297423420