a(n) = A123311(n)/(n+1), where A123311 forms the central terms of triangle A123305.

A123312

a(n) = A123311(n)/(n+1), where A123311 forms the central terms of triangle A123305.

Terms

    a(0) =1a(1) =1a(2) =6a(3) =84a(4) =2010a(5) =70596a(6) =3331006a(7) =199417056a(8) =14559631506

External references