Erroneous version of A005160.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =3a(5) =0a(6) =12a(7) =40a(8) =100a(9) =0a(10) =1225a(11) =6460a(12) =28812a(13) =0a(14) =1037232a(15) =9779616