Expansion of e.g.f. 3*x*exp(x)*(exp(x)-1)^2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =18a(4) =144a(5) =750a(6) =3240a(7) =12642a(8) =46368a(9) =163350a(10) =559800a(11) =1881066a(12) =6229872a(13) =20406750a(14) =66273480a(15) =213759090a(16) =685601856a(17) =2188698150a(18) =6959413080a(19) =22053083514a(20) =69672773520a(21) =219535296750a(22) =690106487400