Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2 n steps taken from {(-1, 0), (1, -1), (1, 1)}.
A151379
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2 n steps taken from {(-1, 0), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =15a(4) =84a(5) =420a(6) =2640a(7) =15015a(8) =100100a(9) =612612a(10) =4232592a(11) =27159132a(12) =192203088a(13) =1274816400a(14) =9178678080a(15) =62386327575a(16) =455053212900
External references
- oeis: A151379