Number of walks within N^2 (the first quadrant of Z^2) starting at (0, 0), ending on the vertical axis and consisting of 2n steps taken from {(-1, -1), (-1, 0), (1, 1)}.
A151374
Number of walks within N^2 (the first quadrant of Z^2) starting at (0, 0), ending on the vertical axis and consisting of 2n steps taken from {(-1, -1), (-1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =2a(2) =8a(3) =40a(4) =224a(5) =1344a(6) =8448a(7) =54912a(8) =366080a(9) =2489344a(10) =17199104a(11) =120393728a(12) =852017152a(13) =6085836800a(14) =43818024960a(15) =317680680960
External references
- oeis: A151374