Number of different lattice paths running from (0,0) to (n,0) using steps from S = {(k,k) or (k,-k): k positive integer} that never go below the x-axis.

A059231

Number of different lattice paths running from (0,0) to (n,0) using steps from S = {(k,k) or (k,-k): k positive integer} that never go below the x-axis.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =29a(4) =185a(5) =1257a(6) =8925a(7) =65445a(8) =491825a(9) =3768209a(10) =29324405a(11) =231153133a(12) =1841801065a(13) =14810069497a(14) =120029657805a(15) =979470140661

External references