Triangle of numbers arising in enumeration of walks on square lattice.

Terms

a(0) =1a(1) =0a(2) =2a(3) =2a(4) =0a(5) =4a(6) =0a(7) =10a(8) =0a(9) =8a(10) =10a(11) =0a(12) =34a(13) =0a(14) =16a(15) =0a(16) =70a(17) =0a(18) =98a(19) =0a(20) =32a(21) =70a(22) =0a(23) =308a(24) =0a(25) =258a(26) =0a(27) =64a(28) =0a(29) =588