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

Terms

a(0) =0a(1) =27a(2) =216a(3) =729a(4) =1728a(5) =3375a(6) =5832a(7) =9261a(8) =13824a(9) =19683a(10) =27000a(11) =35937a(12) =46656a(13) =59319a(14) =74088a(15) =91125a(16) =110592a(17) =132651a(18) =157464a(19) =185193a(20) =216000a(21) =250047a(22) =287496a(23) =328509a(24) =373248a(25) =421875a(26) =474552a(27) =531441a(28) =592704