Bisection of A001790.

Terms

a(0) =1a(1) =5a(2) =63a(3) =429a(4) =12155a(5) =88179a(6) =1300075a(7) =9694845a(8) =583401555a(9) =4418157975a(10) =67282234305a(11) =514589420475