a(n) = 11*binomial(2n,n-5)/(n+6).

Terms

a(0) =1a(1) =11a(2) =77a(3) =440a(4) =2244a(5) =10659a(6) =48279a(7) =211508a(8) =904475a(9) =3798795a(10) =15737865a(11) =64512240a(12) =262256280a(13) =1059111900a(14) =4254603804a(15) =17018415216a(16) =67837293986a(17) =269638992062