A047071 Array T by antidiagonals: T(h,k)=number of paths consisting of steps from (0,0) to (h,k) such that each step has length 1 directed up or right and no step touches the line y=3x unless x=0 or x=h.

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 3, 3, 1, 1, 1, 3, 6, 4, 1, 1, 2, 3, 9, 10, 5, 1, 1, 3, 3, 12, 19, 15, 6, 1, 1, 4, 6, 15, 31, 34, 21, 7, 1, 1, 5, 4, 15, 46, 65, 55, 28, 8, 1, 1, 6, 9, 15, 61, 111, 120, 83, 36, 9, 1, 1, 7, 15, 15, 76, 172, 231, 203, 119, 45

Offset

0,9

Links

Table of n, a(n) for n=0..75.

Example

Antidiagonals (beginning on row 0): {1}; {1,1}; {1,1,1}; {1,1,2,1}; {1,2,3,3,1}; ...

Crossrefs

Cf. A047010 (mirror image).

Sequence in context: A054991 A302918 A316149 * A124287 A253240 A290472

Adjacent sequences: A047068 A047069 A047070 * A047072 A047073 A047074

Keyword

nonn,tabl

Author

Clark Kimberling

Status

approved