Number of peaks at even level in all nondecreasing Dyck paths of semilength n. A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.
A121486
Number of peaks at even level in all nondecreasing Dyck paths of semilength n. A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.
Terms
- a(0) =0a(1) =1a(2) =4a(3) =13a(4) =43a(5) =132a(6) =400a(7) =1184a(8) =3461a(9) =9999a(10) =28634a(11) =81383a(12) =229860a(13) =645731a(14) =1805582a(15) =5028189a(16) =13952221a(17) =38590922a(18) =106434540a(19) =292792026a(20) =803565215a(21) =2200694791a(22) =6015268164a(23) =16412564173a(24) =44708036568a(25) =121600924117a(26) =330277253560
External references
- oeis: A121486