Erroneous duplicate of A000944.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =2a(5) =6a(6) =34a(7) =257a(8) =2606a(9) =440564a(10) =6384634a(11) =96262938a(12) =1496225352a(13) =23833988129a(14) =387591510244