E.g.f.: log(-(-1+x)^2/(-1+2*x)).

Terms

a(0) =0a(1) =0a(2) =2a(3) =12a(4) =84a(5) =720a(6) =7440a(7) =90720a(8) =1280160a(9) =20563200a(10) =370863360a(11) =7424524800a(12) =163419379200