Erroneous version of A003713.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =35a(5) =228a(6) =1834a(7) =17382a(8) =195866a(9) =2487832a(10) =35499576a(11) =562356672a(12) =9794156448a(13) =186025364016