1 if n is a Catalan number else 0.

Terms

a(0) =0a(1) =1a(2) =1a(3) =0a(4) =0a(5) =1a(6) =0a(7) =0a(8) =0a(9) =0a(10) =0a(11) =0a(12) =0a(13) =0a(14) =1a(15) =0a(16) =0a(17) =0a(18) =0a(19) =0a(20) =0a(21) =0a(22) =0a(23) =0a(24) =0a(25) =0a(26) =0a(27) =0a(28) =0a(29) =0