A127832 Array T by antidiagonals: for h>=0 and k>=0, T(h,k)=number of UR paths from (0,0) to (h,k) that touch the line y=2x/3 only at lattice points. A UR path is a path of steps of length 1 each directed up or right.

0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 2, 2, 1, 1, 4, 5, 4, 3, 1, 1, 5, 9, 9, 7, 4, 1, 1, 6, 14, 18, 9, 11, 5, 1, 1, 7, 20, 32, 27, 11, 16, 6, 1, 1, 8, 27, 52, 59, 27, 27, 22, 7, 1, 1, 9, 35, 79, 111, 86, 54, 49, 29, 8, 1, 1, 10, 44, 114, 190, 197, 140, 103, 78, 37, 9, 1, 1, 11, 54, 158, 304, 387

Offset

1,8

Links

Table of n, a(n) for n=1..84.

Example

Northwest corner:
0 1 1 1 1 1
1 1 2 3 4 5
1 1 2 5 9 14
1 2 4 9 18 32
1 3 7 9 27 59
The 4 UR paths for T(3,2) are RRRUU, RRURU, UURRR, URURR. These
paths touch the line y=2x/3 only at the lattice points (0,0) and (3,2).

Crossrefs

Cf. A047110, A127833.

Sequence in context: A284082 A047040 A047020 * A107249 A062842 A126805

Adjacent sequences: A127829 A127830 A127831 * A127833 A127834 A127835

Keyword

nonn,tabl

Author

Clark Kimberling, Feb 01 2007

Status

approved