Number of (1,0)-steps at level zero in all Grand Motzkin paths of length n.

Terms

a(0) =1a(1) =0a(2) =2a(3) =2a(4) =8a(5) =16a(6) =46a(7) =114a(8) =310a(9) =822a(10) =2238a(11) =6094a(12) =16764a(13) =46308a(14) =128650a(15) =358862a(16) =1005056a(17) =2824416a(18) =7962122a(19) =22508350a(20) =63792424a(21) =181219680a(22) =515905018a(23) =1471593638a(24) =4205280902a(25) =12037415526a(26) =34510499066a(27) =99083855234a(28) =284870069780