Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 0), (0, 1), (1, -1), (1, 0)}.
A151283
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 0), (0, 1), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =19a(4) =64a(5) =223a(6) =795a(7) =2885a(8) =10605a(9) =39385a(10) =147476a(11) =555912a(12) =2107242a(13) =8025186a(14) =30685270a(15) =117733427a(16) =453071613a(17) =1748121379a(18) =6760511585a(19) =26198611791a(20) =101712113508a(21) =395531586276
External references
- oeis: A151283