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A198914
T(n,k) = number of n X k 0..7 arrays with values 0..7 introduced in row major order and no element equal to any horizontal or vertical neighbor.
15
1, 1, 1, 2, 4, 2, 5, 34, 34, 5, 15, 500, 2051, 500, 15, 52, 10867, 269940, 269940, 10867, 52, 203, 313132, 54381563, 319608038, 54381563, 313132, 203, 877, 10856948, 13088156547, 481871809749, 481871809749, 13088156547, 10856948, 877, 4139
OFFSET
1,4
COMMENTS
Number of colorings of the grid graph P_n X P_k using a maximum of 8 colors up to permutation of the colors. - Andrew Howroyd, Jun 26 2017
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..276 (terms 1..71 from R. H. Hardin)
EXAMPLE
Table starts
.....1............1..................2......................5
.....1............4.................34....................500
.....2...........34...............2051.................269940
.....5..........500.............269940..............319608038
....15........10867...........54381563...........481871809749
....52.......313132........13088156547........769126451071174
...203.....10856948......3352514013159....1243368053336112649
...877....418689772....876632051686733.2015791720035206825303
..4139..17067989413.230783525290600476
.21110.715189507700
...
Some solutions with values 0 to 7 for n=5, k=3:
..0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0
..1..2..1....1..0..1....1..2..1....1..0..2....1..0..2....1..2..3....1..2..3
..3..0..2....2..3..4....3..4..2....3..4..5....3..4..5....0..1..4....0..4..5
..2..4..5....5..4..3....5..6..1....5..3..6....6..7..0....5..6..7....1..5..1
..1..6..7....6..0..7....6..7..2....7..4..2....3..0..3....7..0..5....6..7..4
CROSSREFS
Columns 1-7 are A099262(n-1), A198908, A198909, A198910, A198911, A198912, A198913.
Main diagonal is A198907.
Cf. A207997 (3 colorings), A198715 (4 colorings), A198906 (5 colorings), A198982 (6 colorings), A198723 (7 colorings), A222462 (labeled 8 colorings), A207868 (unlimited).
Sequence in context: A198906 A198982 A198723 * A207868 A135690 A010241
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin, Oct 31 2011
STATUS
approved