Number of positive walks with n steps {-4,-3,-2,-1,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
A277923
Number of positive walks with n steps {-4,-3,-2,-1,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
Terms
- a(0) =0a(1) =1a(2) =3a(3) =16a(4) =84a(5) =505a(6) =3121a(7) =20180a(8) =133604a(9) =904512a(10) =6224305a(11) =43432093a(12) =306524670a(13) =2184389874a(14) =15695947669a(15) =113595885023a(16) =827299204132
External references
- oeis: A277923