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, 0)}.
A151416
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, 0)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =37a(6) =109a(7) =334a(8) =1049a(9) =3367a(10) =10992a(11) =36399a(12) =121982a(13) =412969a(14) =1410446a(15) =4854123a(16) =16818222a(17) =58617286a(18) =205384162a(19) =723043647a(20) =2556317905a(21) =9072825097a(22) =32314370528a(23) =115462754160a(24) =413775789826
External references
- oeis: A151416