Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 1), (0, -1), (0, 1), (1, 0), (1, 1)}.
A151460
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 1), (0, -1), (0, 1), (1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =12a(4) =44a(5) =164a(6) =643a(7) =2574a(8) =10554a(9) =43956a(10) =185642a(11) =792846a(12) =3418616a(13) =14860606a(14) =65054182a(15) =286536007a(16) =1268905654a(17) =5646284864a(18) =25232338903a(19) =113194654758a(20) =509574041184
External references
- oeis: A151460