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, 0), (1, 1)}.
A151445
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, 0), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =16a(5) =49a(6) =165a(7) =538a(8) =1881a(9) =6673a(10) =23954a(11) =87931a(12) =326739a(13) =1224662a(14) =4649697a(15) =17778696a(16) =68513483a(17) =265907818a(18) =1038089219a(19) =4074688736a(20) =16076107171a(21) =63703583554a(22) =253492204031
External references
- oeis: A151445