Erroneous version of A030532.

Terms

a(0) =0a(1) =1a(2) =6a(3) =35a(4) =168a(5) =807a(6) =3738a(7) =17326a(8) =79909a(9) =369366a(10) =1709123a(11) =7929590a(12) =36880231