Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of 2 n steps taken from {(-1, -1), (-1, 1), (0, 1), (1, -1)}.
A151333
Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of 2 n steps taken from {(-1, -1), (-1, 1), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =0a(2) =2a(3) =6a(4) =42a(5) =308a(6) =2424a(7) =21118a(8) =194010a(9) =1866896a(10) =18674908a(11) =192737280a(12) =2042585592a(13) =22142680360a(14) =244772420336
External references
- oeis: A151333