Number of Motzkin paths of length n with no peaks at level 1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =5a(5) =12a(6) =29a(7) =72a(8) =183a(9) =473a(10) =1239a(11) =3282a(12) =8777a(13) =23665a(14) =64261a(15) =175584a(16) =482395a(17) =1331795a(18) =3692891a(19) =10280190a(20) =28719659a(21) =80493514a(22) =226268539a(23) =637767720a(24) =1802113489a(25) =5103874135a(26) =14485789561a(27) =41194844114a(28) =117366166381