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

A268429

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

Terms

    a(0) =1a(1) =4a(2) =16a(3) =62a(4) =238a(5) =910a(6) =3475a(7) =13270a(8) =50707a(9) =193948a(10) =742659a(11) =2847126a(12) =10928009a(13) =41993692a(14) =161555008a(15) =622201838a(16) =2398811962a(17) =9257512318a(18) =35760612784a(19) =138263710226a(20) =535038428936

External references