Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 1), (0, 1), (1, -1), (1, 0), (1, 1)}.

A151462

Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 1), (0, 1), (1, -1), (1, 0), (1, 1)}.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =8a(4) =27a(5) =89a(6) =320a(7) =1158a(8) =4347a(9) =16510a(10) =63903a(11) =249952a(12) =989110a(13) =3947056a(14) =15878333a(15) =64296723a(16) =261931840a(17) =1072616649a(18) =4413123474a(19) =18233286270a(20) =75619434417a(21) =314696837489

External references