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), (1, -1), (1, 1)}.
A151414
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), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =2a(4) =6a(5) =14a(6) =43a(7) =126a(8) =396a(9) =1230a(10) =3970a(11) =12830a(12) =42478a(13) =140982a(14) =475671a(15) =1608542a(16) =5508488a(17) =18900350a(18) =65498136a(19) =227340182a(20) =795468118a(21) =2787057078a(22) =9830186006a(23) =34711199838a(24) =123255087526a(25) =438093298054
External references
- oeis: A151414