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), (-1, 0), (0, 1), (1, -1), (1, 0), (1, 1)}.
A151476
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), (-1, 0), (0, 1), (1, -1), (1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =13a(4) =52a(5) =221a(6) =969a(7) =4476a(8) =21050a(9) =101708a(10) =499482a(11) =2491362a(12) =12586523a(13) =64275443a(14) =331393163a(15) =1722648256a(16) =9020489609a(17) =47541144560a(18) =252014613424
External references
- oeis: A151476