Number of North-East lattice paths from (0,0) to (n,n) that bounce off the diagonal y = x to the right exactly four times.

A268402

Number of North-East lattice paths from (0,0) to (n,n) that bounce off the diagonal y = x to the right exactly four times.

Terms

    a(0) =1a(1) =7a(2) =40a(3) =204a(4) =977a(5) =4493a(6) =20091a(7) =88025a(8) =379766a(9) =1618898a(10) =6835636a(11) =28640302a(12) =119236085a(13) =493772409a(14) =2035611612a(15) =8359873866a(16) =34219553297a(17) =139672169795a(18) =568675783762

External references