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), (1, -1), (1, 0)}.
A151439
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), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =7a(4) =22a(5) =74a(6) =269a(7) =1022a(8) =3987a(9) =15897a(10) =64787a(11) =268685a(12) =1130049a(13) =4810797a(14) =20700879a(15) =89918115a(16) =393811281a(17) =1737451533a(18) =7716025961a(19) =34470611627a(20) =154822298289a(21) =698772455153
External references
- oeis: A151439