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), (0, 1), (1, -1), (1, 1)}.
A151478
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), (0, 1), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =12a(4) =54a(5) =210a(6) =1020a(7) =4445a(8) =22610a(9) =105210a(10) =551376a(11) =2678676a(12) =14332164a(13) =71788860a(14) =389991888a(15) =1998530820a(16) =10984120290a(17) =57293297490a(18) =317798892840
External references
- oeis: A151478