Number of walks of length n on square lattice, starting at origin, staying in first, second and third quadrants.

A060898

Number of walks of length n on square lattice, starting at origin, staying in first, second and third quadrants.

Terms

    a(0) =1a(1) =4a(2) =14a(3) =54a(4) =200a(5) =776a(6) =2940a(7) =11466a(8) =43980a(9) =172170a(10) =665544a(11) =2612764a(12) =10154144a(13) =39949000a(14) =155864280a(15) =614260062a(16) =2403739140a(17) =9486263092a(18) =37209147800a(19) =147012850512a(20) =577741491404

External references