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, 0), (-1, 1), (0, -1), (0, 1), (1, 0), (1, 1)}.
A151491
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, 0), (-1, 1), (0, -1), (0, 1), (1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =7a(3) =25a(4) =139a(5) =697a(6) =3908a(7) =21912a(8) =127422a(9) =750754a(10) =4500751a(11) =27294099a(12) =167326836a(13) =1034813515a(14) =6449427761a(15) =40464120538a(16) =255370900987
External references
- oeis: A151491