Number of nondecreasing Dyck paths of semilength n and having no peaks at odd level (n>=0). A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.

A121482

Number of nondecreasing Dyck paths of semilength n and having no peaks at odd level (n>=0). A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =5a(6) =12a(7) =22a(8) =49a(9) =94a(10) =201a(11) =396a(12) =828a(13) =1656a(14) =3421a(15) =6899a(16) =14160a(17) =28686a(18) =58672a(19) =119156a(20) =243253a(21) =494688a(22) =1008860a(23) =2053168a(24) =4184892a(25) =8520248a(26) =17361293a(27) =35354517a(28) =72028485a(29) =146696143

External references