Binomial coefficient C(4n,n-6).

Terms

a(0) =1a(1) =28a(2) =496a(3) =7140a(4) =91390a(5) =1086008a(6) =12271512a(7) =133784560a(8) =1420494075a(9) =14783142660a(10) =151473214816