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

Terms

a(0) =1a(1) =2a(2) =9a(3) =28a(4) =95a(5) =306a(6) =987a(7) =3144a(8) =9963a(9) =31390a(10) =98483a(11) =307836a(12) =959257a(13) =2981174a(14) =9243405a(15) =28601712a(16) =88342659a(17) =272428758a(18) =838903371a(19) =2579937060a(20) =7924966749a(21) =24317716038a(22) =74546117121a(23) =228317474952a(24) =698708409525