Number of positive walks with n steps {-4,-3,-2,-1,0,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
A277921
Number of positive walks with n steps {-4,-3,-2,-1,0,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
Terms
- a(0) =0a(1) =1a(2) =4a(3) =23a(4) =142a(5) =950a(6) =6662a(7) =48420a(8) =361378a(9) =2753687a(10) =21334313a(11) =167551836a(12) =1330894754a(13) =10673486660a(14) =86306300366a(15) =702872359332
External references
- oeis: A277921