Stirling_2 transform of A002487.

Terms

a(0) =1a(1) =3a(2) =8a(3) =24a(4) =88a(5) =381a(6) =1822a(7) =9254a(8) =49295a(9) =275219a(10) =1614968a(11) =9993871a(12) =65442602a(13) =454736731a(14) =3356546167a(15) =26272011685a(16) =217027548533