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), (0, 1), (1, 0), (1, 1)}.

A151444

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), (0, 1), (1, 0), (1, 1)}.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =8a(4) =26a(5) =88a(6) =311a(7) =1153a(8) =4333a(9) =16829a(10) =66002a(11) =264115a(12) =1066884a(13) =4363921a(14) =18002965a(15) =74905311a(16) =313910581a(17) =1323968067a(18) =5616942579a(19) =23952413637a(20) =102631047883a(21) =441627135110

External references