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), (1, -1), (1, 0)}.
A151358
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), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =3a(4) =7a(5) =29a(6) =101a(7) =404a(8) =1657a(9) =6987a(10) =30666a(11) =136679a(12) =624485a(13) =2899186a(14) =13670079a(15) =65344840a(16) =316012215a(17) =1544872132a(18) =7624022772a(19) =37951505458a(20) =190398999412a(21) =962031788591
External references
- oeis: A151358