Triangle read by rows: Kreweras's "Rule A_4 left thickness" numbers.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =6a(5) =4a(6) =1a(7) =16a(8) =20a(9) =8a(10) =1a(11) =48a(12) =76a(13) =56a(14) =16a(15) =1a(16) =170a(17) =284a(18) =272a(19) =144a(20) =32a(21) =1a(22) =686a(23) =1128a(24) =1200a(25) =848a(26) =352a(27) =64a(28) =1a(29) =3008