The number of paths of length 2m in the plane, starting and ending at (0,1), with unit steps in the four directions (north, east, south, west) and staying in the region y > 0 or x > -y.

A292361

The number of paths of length 2m in the plane, starting and ending at (0,1), with unit steps in the four directions (north, east, south, west) and staying in the region y > 0 or x > -y.

Terms

    a(0) =1a(1) =3a(2) =21a(3) =192a(4) =2009a(5) =22818a(6) =273895a(7) =3421318a(8) =44042729a(9) =580473551a(10) =7796745921a(11) =106365396629

External references