Column 1 of triangle A228900.

A228901

Column 1 of triangle A228900.

Terms

    a(0) =1a(1) =3a(2) =15a(3) =155a(4) =2685a(5) =65517a(6) =2063205a(7) =79715229a(8) =3653521179a(9) =193876702019

External references