Central terms of triangle A127126; a(n) = A127126(2n,n).

A127134

Central terms of triangle A127126; a(n) = A127126(2n,n).

Terms

    a(0) =1a(1) =2a(2) =18a(3) =284a(4) =6680a(5) =211398a(6) =8439235a(7) =407247048a(8) =23056215138

External references