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, 1), (0, -1), (1, 1)}.
A151389
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, 1), (0, -1), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =2a(3) =2a(4) =10a(5) =22a(6) =82a(7) =220a(8) =808a(9) =2356a(10) =8656a(11) =26654a(12) =98102a(13) =312984a(14) =1156032a(15) =3782616a(16) =14015132a(17) =46756952a(18) =173680748a(19) =588380312a(20) =2190211648a(21) =7512444672a(22) =28014835088a(23) =97081546938a(24) =362582983586
External references
- oeis: A151389