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), (-1, 1), (0, 1), (1, -1), (1, 1)}.
A151440
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), (-1, 1), (0, 1), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =8a(4) =30a(5) =104a(6) =418a(7) =1619a(8) =6811a(9) =27995a(10) =121479a(11) =518165a(12) =2298497a(13) =10057101a(14) =45342297a(15) =202127226a(16) =922674852a(17) =4172053826a(18) =19231818364a(19) =87941092870a(20) =408591525432
External references
- oeis: A151440