Riordan array (1, x*(1-x)/(1-3*x+x^2)).

Terms

a(0) =1a(1) =2a(2) =1a(3) =5a(4) =4a(5) =1a(6) =13a(7) =14a(8) =6a(9) =1a(10) =34a(11) =46a(12) =27a(13) =8a(14) =1a(15) =89a(16) =145a(17) =107a(18) =44a(19) =10a(20) =1a(21) =233a(22) =444a(23) =393a(24) =204a(25) =65a(26) =12a(27) =1a(28) =610a(29) =1331