Number of lattice paths from (0,0) to (n,n) using steps S={(k,0),(0,k),(1,1)|0<k<=2} which never go above the line y=x.

A175895

Number of lattice paths from (0,0) to (n,n) using steps S={(k,0),(0,k),(1,1)|0<k<=2} which never go above the line y=x.

Terms

    a(0) =1a(1) =2a(2) =9a(3) =50a(4) =314a(5) =2116a(6) =14949a(7) =109246a(8) =818978a(9) =6263072a(10) =48668366a(11) =383182648a(12) =3050196328a(13) =24506969724a(14) =198482172753

External references