Number of nondecreasing Dyck paths of semilength n and having no peaks at even level (n>=0). A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.
A121485
Number of nondecreasing Dyck paths of semilength n and having no peaks at even 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) =1a(2) =2a(3) =4a(4) =8a(5) =16a(6) =33a(7) =66a(8) =136a(9) =274a(10) =562a(11) =1138a(12) =2327a(13) =4725a(14) =9645a(15) =19613a(16) =39997a(17) =81397a(18) =165906a(19) =337773a(20) =688260a(21) =1401565a(22) =2855432a(23) =5815477a(24) =11846941a(25) =24129498a(26) =49152840a(27) =100116607a(28) =203936639a(29) =415394872
External references
- oeis: A121485