G.f.: 5/(2 + 3*sqrt(1-20*x)).

Terms

a(0) =1a(1) =6a(2) =66a(3) =876a(4) =12786a(5) =197796a(6) =3183156a(7) =52718616a(8) =892401426a(9) =15368638836a(10) =268388185596