a(n) is the number of paths with length 3*n that begin at (0,0), end at (0,0), and do not reach (0,0) at any point in between while 0 <= y <= x at every step, where a path is a sequence of steps in the form (1,1), (1,-1), and (-2,0).
A364439
a(n) is the number of paths with length 3*n that begin at (0,0), end at (0,0), and do not reach (0,0) at any point in between while 0 <= y <= x at every step, where a path is a sequence of steps in the form (1,1), (1,-1), and (-2,0).
Terms
- a(0) =1a(1) =1a(2) =4a(3) =33a(4) =367a(5) =4844a(6) =71597a(7) =1147653a(8) =19559062a(9) =349766457a(10) =6502419671a(11) =124822220086
External references
- oeis: A364439