Column 0 of triangle A121420.

A121421

Column 0 of triangle A121420.

Terms

    a(0) =1a(1) =3a(2) =12a(3) =76a(4) =711a(5) =9054a(6) =147471a(7) =2938176a(8) =69328365a(9) =1891371807a(10) =58575539361

External references