a(n) = 7*n^3.

Terms

a(0) =0a(1) =7a(2) =56a(3) =189a(4) =448a(5) =875a(6) =1512a(7) =2401a(8) =3584a(9) =5103a(10) =7000a(11) =9317a(12) =12096a(13) =15379a(14) =19208a(15) =23625a(16) =28672a(17) =34391a(18) =40824a(19) =48013a(20) =56000a(21) =64827a(22) =74536a(23) =85169a(24) =96768a(25) =109375a(26) =123032a(27) =137781a(28) =153664a(29) =170723