Binomial coefficient C(2n,n-5).

Terms

a(0) =1a(1) =12a(2) =91a(3) =560a(4) =3060a(5) =15504a(6) =74613a(7) =346104a(8) =1562275a(9) =6906900a(10) =30045015a(11) =129024480a(12) =548354040a(13) =2310789600a(14) =9669554100a(15) =40225345056a(16) =166509721602a(17) =686353797976