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

Terms

a(0) =1a(1) =11a(2) =85a(3) =575a(4) =3661a(5) =22631a(6) =137845a(7) =833375a(8) =5019421a(9) =30174551a(10) =181222405a(11) =1087861775a(12) =6528756781a(13) =39177307271a(14) =235078159765