Number of Dyck paths of semilength n having exactly 2 (possibly overlapping) occurrences of the consecutive steps UDUUUDDDUD (with U=(1,1), D=(1,-1)).
A243872
Number of Dyck paths of semilength n having exactly 2 (possibly overlapping) occurrences of the consecutive steps UDUUUDDDUD (with U=(1,1), D=(1,-1)).
Terms
- a(0) =1a(1) =4a(2) =16a(3) =65a(4) =263a(5) =1077a(6) =4419a(7) =18132a(8) =74368a(9) =304778a(10) =1247972a(11) =5105477a(12) =20867862a(13) =85219608a(14) =347724794a(15) =1417697157a(16) =5775652743a(17) =23512922998a(18) =95657223246a(19) =388912046916
External references
- oeis: A243872