Column 2 of A007754.

Terms

a(0) =1a(1) =3a(2) =11a(3) =52a(4) =301a(5) =2055a(6) =16139a(7) =143196a(8) =1415821a(9) =15430835a(10) =183754199a(11) =2373373752a(12) =33043478329a(13) =493278801183