Number of pairs of nested Dyck paths from (0,0) to (n,n) such that the upper path only touches the diagonal at its endpoints.

A355281

Number of pairs of nested Dyck paths from (0,0) to (n,n) such that the upper path only touches the diagonal at its endpoints.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =9a(4) =55a(5) =400a(6) =3266a(7) =28999a(8) =274537a(9) =2734885a(10) =28401315a(11) =305352146a(12) =3380956839a(13) =38394091370a(14) =445702108969

External references