Expansion of g.f. x^2*(1+4*x-3*x^2)/((1-x)^2*(1-2*x)*(1-3*x)).

Terms

a(0) =0a(1) =0a(2) =1a(3) =11a(4) =57a(5) =229a(6) =815a(7) =2715a(8) =8701a(9) =27233a(10) =83979a(11) =256519a(12) =778745a(13) =2354637a(14) =7100743a(15) =21375923a(16) =64275189a(17) =193120441a(18) =579951107a(19) =1741032927a(20) =5225458033a(21) =15681092645a(22) =47052715071a(23) =141177019531a(24) =423568807277