A skew generalized Pascal triangle.

Terms

a(0) =1a(1) =0a(2) =3a(3) =0a(4) =1a(5) =10a(6) =0a(7) =0a(8) =6a(9) =33a(10) =0a(11) =0a(12) =1a(13) =29a(14) =109a(15) =0a(16) =0a(17) =0a(18) =9a(19) =126a(20) =360a(21) =0a(22) =0a(23) =0a(24) =1a(25) =57a(26) =516a(27) =1189a(28) =0a(29) =0