Dirichlet convolution of phi(n) with Catalan numbers.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =18a(5) =48a(6) =138a(7) =440a(8) =1440a(9) =4884a(10) =16806a(11) =58848a(12) =208024a(13) =743044a(14) =2674484a(15) =9695296a(16) =35357686a(17) =129646320a(18) =477638718a(19) =1767268112a(20) =6564120708a(21) =24466283836a(22) =91482563662a(23) =343059673408