Riordan array (1/sqrt(1-4*x), (1/sqrt(1-4*x)-1)/2).

Terms

a(0) =1a(1) =2a(2) =1a(3) =6a(4) =5a(5) =1a(6) =20a(7) =22a(8) =8a(9) =1a(10) =70a(11) =93a(12) =47a(13) =11a(14) =1a(15) =252a(16) =386a(17) =244a(18) =81a(19) =14a(20) =1a(21) =924a(22) =1586a(23) =1186a(24) =500a(25) =124a(26) =17a(27) =1a(28) =3432a(29) =6476