Number of Motzkin paths of length n with no level steps at height 4.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =21a(6) =51a(7) =127a(8) =323a(9) =834a(10) =2179a(11) =5743a(12) =15238a(13) =40637a(14) =108800a(15) =292200a(16) =786703a(17) =2122387a(18) =5735596a(19) =15522682a(20) =42064028a(21) =114117541a(22) =309918698a(23) =842489130a(24) =2292332265a(25) =6242655886