a(n) = (8*n + 4)^3.

Terms

a(0) =64a(1) =1728a(2) =8000a(3) =21952a(4) =46656a(5) =85184a(6) =140608a(7) =216000a(8) =314432a(9) =438976a(10) =592704a(11) =778688a(12) =1000000a(13) =1259712a(14) =1560896a(15) =1906624a(16) =2299968a(17) =2744000a(18) =3241792a(19) =3796416a(20) =4410944a(21) =5088448a(22) =5832000a(23) =6644672a(24) =7529536a(25) =8489664a(26) =9528128a(27) =10648000a(28) =11852352a(29) =13144256