Number of Motzkin excursions of length n with an odd number of humps.

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =7a(5) =15a(6) =32a(7) =70a(8) =161a(9) =393a(10) =1012a(11) =2706a(12) =7392a(13) =20384a(14) =56359a(15) =155801a(16) =430497a(17) =1190017a(18) =3295100a(19) =9149602a(20) =25495910a(21) =71318078a(22) =200242825a(23) =564166011a(24) =1594291230a(25) =4517054710a(26) =12826583811a(27) =36493143333a(28) =104008257711a(29) =296906934031