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), (0, 1), (1, -1), (1, 0)}.
A151458
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), (0, 1), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =8a(4) =26a(5) =88a(6) =315a(7) =1171a(8) =4477a(9) =17546a(10) =70066a(11) =284471a(12) =1170797a(13) =4876190a(14) =20517751a(15) =87111609a(16) =372793818a(17) =1606639972a(18) =6968002247a(19) =30392051069a(20) =133241561658a(21) =586871095960
External references
- oeis: A151458