Number of self-avoiding planar walks starting at (0,0), ending at (n,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restrictions that (0,1) and (1,-1) are never used above the diagonal and (1,0) and (-1,1) are never used below the diagonal and (1,1) can only be used below the diagonal.

A303477

Number of self-avoiding planar walks starting at (0,0), ending at (n,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restrictions that (0,1) and (1,-1) are never used above the diagonal and (1,0) and (-1,1) are never used below the diagonal and (1,1) can only be used below the diagonal.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =16a(5) =51a(6) =186a(7) =675a(8) =2619a(9) =10222a(10) =41278a(11) =168322a(12) =699654a(13) =2936170a(14) =12472461a(15) =53415773a(16) =230718087a(17) =1003219186a(18) =4390238536a(19) =19317023478a(20) =85423978859a(21) =379448391283

External references