a(n) = C(2n,n)*Bell(n).

Terms

a(0) =1a(1) =2a(2) =12a(3) =100a(4) =1050a(5) =13104a(6) =187572a(7) =3009864a(8) =53281800a(9) =1028167140a(10) =21427077100a(11) =478684992240