a(n) = binomial coefficient C(2n, n-9).

Terms

a(0) =1a(1) =20a(2) =231a(3) =2024a(4) =14950a(5) =98280a(6) =593775a(7) =3365856a(8) =18156204a(9) =94143280a(10) =472733756a(11) =2311801440a(12) =11058116888a(13) =51915526432a(14) =239877544005