a(n) = prime(Catalan(n)).

Terms

a(0) =2a(1) =2a(2) =3a(3) =11a(4) =43a(5) =181a(6) =743a(7) =2971a(8) =11933a(9) =47129a(10) =185569a(11) =729947a(12) =2868191a(13) =11265517a(14) =44230699a(15) =173632489a(16) =681785497a(17) =2677741049a(18) =10520707411a(19) =41351166313a(20) =162595828093a(21) =639609298351