Binomial coefficient C(4n,n-9).

Terms

a(0) =1a(1) =40a(2) =946a(3) =17296a(4) =270725a(5) =3819816a(6) =50063860a(7) =621216192a(8) =7392009768a(9) =85113005120a(10) =954526728530