a(n) = Sum_{k=0..n} (-1)^k * binomial(5*k,n-k) * Catalan(k).

Terms

a(0) =1a(1) =-1a(2) =-3a(3) =5a(4) =19a(5) =-52a(6) =-114a(7) =570a(8) =470a(9) =-6026a(10) =2156a(11) =59311a(12) =-93869a(13) =-519805a(14) =1668241a(15) =3635670a(16) =-23289426a(17) =-11134840a(18) =280455900a(19) =-238282316a(20) =-2944763030a(21) =6683843250a(22) =25804836482a(23) =-113673966635a(24) =-155130413515a(26) =-253144380823