Binomial coefficient C(2n,n-6).

Terms

a(0) =1a(1) =14a(2) =120a(3) =816a(4) =4845a(5) =26334a(6) =134596a(7) =657800a(8) =3108105a(9) =14307150a(10) =64512240a(11) =286097760a(12) =1251677700a(13) =5414950296a(14) =23206929840a(15) =98672427616a(16) =416714805914