a(n)^3 is smallest cube containing exactly n 2's.

Terms

a(0) =3a(1) =28a(2) =138a(3) =587a(4) =612a(5) =2824a(6) =27654a(7) =29603a(8) =131468a(9) =1312748a(10) =1616488a(11) =2811574a(12) =49629974a(13) =139796852a(14) =281986403a(15) =1264554822a(16) =6146857824a(17) =16162692208a(18) =60598584603a(19) =229717543765a(20) =606069984352