a(n) = (3*n + 1)^3.

Terms

a(0) =1a(1) =64a(2) =343a(3) =1000a(4) =2197a(5) =4096a(6) =6859a(7) =10648a(8) =15625a(9) =21952a(10) =29791a(11) =39304a(12) =50653a(13) =64000a(14) =79507a(15) =97336a(16) =117649a(17) =140608a(18) =166375a(19) =195112a(20) =226981a(21) =262144a(22) =300763a(23) =343000a(24) =389017a(25) =438976a(26) =493039a(27) =551368a(28) =614125a(29) =681472