Number of Dyck paths of semilength n having exactly two (possibly overlapping) DUDU's (with U=(1,1), D=(1,-1)).
A263173
Number of Dyck paths of semilength n having exactly two (possibly overlapping) DUDU's (with U=(1,1), D=(1,-1)).
Terms
- a(0) =1a(1) =3a(2) =15a(3) =58a(4) =231a(5) =891a(6) =3403a(7) =12870a(8) =48318a(9) =180356a(10) =670014a(11) =2479302a(12) =9143885a(13) =33627777a(14) =123366789a(15) =451612846a(16) =1650111453a(17) =6019100025a(18) =21922936343a(19) =79740801036a(20) =289690000380
External references
- oeis: A263173