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)}.
A151380
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)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =2a(4) =4a(5) =8a(6) =23a(7) =58a(8) =142a(9) =352a(10) =982a(11) =2620a(12) =6910a(13) =18328a(14) =51361a(15) =141022a(16) =385266a(17) =1055936a(18) =2981288a(19) =8329488a(20) =23219142a(21) =64864824a(22) =184401956a(23) =521245736a(24) =1471964582a(25) =4163298128a(26) =11904910448a(27) =33933381248a(28) =96692013158a(29) =275858766248
External references
- oeis: A151380