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

A151453

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

Terms

    a(0) =1a(1) =4a(2) =42a(3) =578a(4) =9166a(5) =158242a(6) =2891042a(7) =54993704a(8) =1078134132a(9) =21636311154a(10) =442364872960

External references