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

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =10a(5) =8a(6) =10a(7) =34a(8) =16a(9) =70a(10) =98a(11) =32a(12) =70a(13) =308a(14) =258a(15) =64a(16) =588a(17) =1092a(18) =642a(19) =128a(20) =588a(21) =3024a(22) =3414a(23) =1538a(24) =256a(25) =5544a(26) =12276a(27) =9834a(28) =3586a(29) =512