The Fuss-Catalan triangle of order 2, read by rows. Related to ternary trees.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =1a(5) =3a(6) =0a(7) =1a(8) =5a(9) =12a(10) =0a(11) =1a(12) =7a(13) =25a(14) =55a(15) =0a(16) =1a(17) =9a(18) =42a(19) =130a(20) =273a(21) =0a(22) =1a(23) =11a(24) =63a(25) =245a(26) =700a(27) =1428a(28) =0a(29) =1