Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1)}.
A151349
Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =1a(4) =5a(5) =8a(6) =40a(7) =91a(8) =406a(9) =1167a(10) =4956a(11) =16349a(12) =68312a(13) =246502a(14) =1027322a(15) =3938800a(16) =16499271a(17) =65979431a(18) =278832735a(19) =1149369374a(20) =4907324239a(21) =20691994829a(22) =89274013063a(23) =383084876832
External references
- oeis: A151349