Number of all self-avoiding planar walks of length j (0<=j<=n) starting at (0,0), ending at (n-j,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restriction that (0,1) is never used below the diagonal and (1,0) is never used above the diagonal.

A284428

Number of all self-avoiding planar walks of length j (0<=j<=n) starting at (0,0), ending at (n-j,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restriction that (0,1) is never used below the diagonal and (1,0) is never used above the diagonal.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =2a(5) =1a(6) =5a(7) =5a(8) =13a(9) =15a(10) =40a(11) =44a(12) =123a(13) =156a(14) =402a(15) =536a(16) =1361a(17) =1857a(18) =4689a(19) =6681a(20) =16536a(21) =24286a(22) =59400a(23) =89131a(24) =216114a(25) =331324a(26) =796029a(27) =1243168a(28) =2963859a(29) =4700410

External references