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), (-1, 1), (0, 1), (1, -1)}.
A151420
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), (-1, 1), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =3a(4) =9a(5) =20a(6) =60a(7) =196a(8) =589a(9) =1907a(10) =6516a(11) =21860a(12) =75589a(13) =267566a(14) =950279a(15) =3423629a(16) =12499661a(17) =45919855a(18) =170274916a(19) =636617648a(20) =2394733039a(21) =9067049073a(22) =34535991913a(23) =132213431523a(24) =508684283599
External references
- oeis: A151420