Number of paths from (0,0) to (3n,0) that stay in the first quadrant, consist of steps u=(2,1), U=(1,2), or d=(1,-1) and do not touch the x-axis, except at the endpoints.
A108424
Number of paths from (0,0) to (3n,0) that stay in the first quadrant, consist of steps u=(2,1), U=(1,2), or d=(1,-1) and do not touch the x-axis, except at the endpoints.
Terms
- a(0) =2a(1) =6a(2) =34a(3) =238a(4) =1858a(5) =15510a(6) =135490a(7) =1223134a(8) =11320066a(9) =106830502a(10) =1024144482a(11) =9945711566a(12) =97634828354a(13) =967298498358
External references
- oeis: A108424