Number of 2n-step paths from (0,0) to (0,n) that stay in the first quadrant (but may touch the axes) consisting of steps (1,0), (0,1), (0,-1) and (-1,1).

A317782

Number of 2n-step paths from (0,0) to (0,n) that stay in the first quadrant (but may touch the axes) consisting of steps (1,0), (0,1), (0,-1) and (-1,1).

Terms

    a(0) =1a(1) =1a(2) =5a(3) =51a(4) =474a(5) =4329a(6) =43406a(7) =469565a(8) =5228459a(9) =59259957a(10) =686003702a(11) =8097484169a(12) =97005128492

External references