Number of Dyck paths of semilength n+4, having exactly two long ascents (i.e., ascents of length at least two).

A091135

Number of Dyck paths of semilength n+4, having exactly two long ascents (i.e., ascents of length at least two).

Terms

    a(0) =2a(1) =15a(2) =69a(3) =252a(4) =804a(5) =2349a(6) =6455a(7) =16962a(8) =43086a(9) =106587a(10) =258153a(11) =614520a(12) =1441928a(13) =3342489a(14) =7667883a(15) =17432766a(16) =39321810a(17) =88080615a(18) =196083965a(19) =434110740a(20) =956301612a(21) =2097152325a(22) =4580180319a(23) =9965666682a(24) =21609054614a(25) =46707769779

External references