a(n) = 9^n*Catalan(n).A156273a(n) = 9^n*Catalan(n).Terms a(0) =1a(1) =9a(2) =162a(3) =3645a(4) =91854a(5) =2480058a(6) =70150212a(7) =2051893701a(8) =61556811030External referencesoeis: A156273