A207981 T(n,k)=Number of n X k nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any diagonal or antidiagonal neighbor (colorings ignoring permutations of colors).

1, 2, 2, 5, 7, 5, 15, 67, 67, 15, 52, 1080, 4192, 1080, 52, 203, 25287, 587208, 587208, 25287, 203, 877, 794545, 147512732, 953124784, 147512732, 794545, 877, 4140, 31858034, 58668937932, 3410310590912, 3410310590912, 58668937932, 31858034

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..496 (terms 1..40 from R. H. Hardin).

Example

Table starts
....1........2...........5............15............52...............203
....2........7..........67..........1080.........25287............794545
....5.......67........4192........587208.....147512732.......58668937932
...15.....1080......587208.....953124784.3410310590912.22727131144960768
...52....25287...147512732.3410310590912
..203...794545.58668937932
..877.31858034
.4140
...
Some solutions for n=4 k=3
..0..0..0....0..0..1....0..0..0....0..0..0....0..1..0....0..0..0....0..0..0
..1..1..1....1..2..1....1..1..1....1..1..1....2..1..0....1..2..1....1..1..1
..2..0..2....1..2..0....0..0..2....0..0..0....0..1..3....0..0..0....2..2..0
..1..0..1....0..2..0....1..1..1....1..1..1....0..4..0....2..1..1....0..1..0

Crossrefs

Columns 1..4 are A000110, A207978, A207979, A207980.

Main diagonal is A361452.

Cf. A207868.

Sequence in context: A136536 A023507 A095674 * A058123 A035586 A216392

Adjacent sequences: A207978 A207979 A207980 * A207982 A207983 A207984

Keyword

nonn,tabl

Author

R. H. Hardin, Feb 22 2012

Status

approved