a(n) = (3*n)!*(10*n)!/((2*n)!*(5*n)!*(6*n)!).

A364402

a(n) = (3*n)!*(10*n)!/((2*n)!*(5*n)!*(6*n)!).

Terms

    a(0) =1a(1) =126a(2) =41990a(3) =15967980a(4) =6421422150

External references