A triangle of Motzkin ballot numbers, read by rows.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =1a(7) =3a(8) =3a(9) =2a(10) =1a(11) =4a(12) =6a(13) =6a(14) =4a(15) =1a(16) =5a(17) =10a(18) =13a(19) =13a(20) =9a(21) =1a(22) =6a(23) =15a(24) =24a(25) =30a(26) =30a(27) =21a(28) =1a(29) =7