Expansion of 1 / ( (1-3*x) * (1-6*x) )^(2/3).

Terms

a(0) =1a(1) =6a(2) =33a(3) =180a(4) =990a(5) =5508a(6) =30978a(7) =175824a(8) =1005345a(9) =5782590a(10) =33418737a(11) =193876092a(12) =1128297276a(13) =6583492080a(14) =38498441400a(15) =225550220544