a(n) = 5^n * Catalan(n).

Terms

a(0) =1a(1) =5a(2) =50a(3) =625a(4) =8750a(5) =131250a(6) =2062500a(7) =33515625a(8) =558593750a(9) =9496093750a(10) =164023437500