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, 1)}.
A151417
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, 1)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =40a(6) =122a(7) =380a(8) =1217a(9) =3967a(10) =13137a(11) =44053a(12) =149321a(13) =510735a(14) =1760687a(15) =6111171a(16) =21338857a(17) =74906438a(18) =264192659a(19) =935757437a(20) =3327107090a(21) =11870683108a(22) =42486960839a(23) =152506832992a(24) =548875377127
External references
- oeis: A151417