a(n) = Catalan(n) * Product_{k = 0..n-1} a(k).

A003047

a(n) = Catalan(n) * Product_{k = 0..n-1} a(k).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =10a(4) =280a(5) =235200a(6) =173859840000

External references