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A220553 T(n,k)=Number of ways to reciprocally link elements of an nXk array either to themselves or to exactly one horizontal, vertical or antidiagonal neighbor 8
1, 2, 2, 3, 8, 3, 5, 29, 29, 5, 8, 108, 224, 108, 8, 13, 401, 1814, 1814, 401, 13, 21, 1490, 14556, 32173, 14556, 1490, 21, 34, 5536, 117022, 565061, 565061, 117022, 5536, 34, 55, 20569, 940432, 9943416, 21668208, 9943416, 940432, 20569, 55, 89, 76424 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Table starts
...1.......2...........3...............5...................8
...2.......8..........29.............108.................401
...3......29.........224............1814...............14556
...5.....108........1814...........32173..............565061
...8.....401.......14556..........565061............21668208
..13....1490......117022.........9943416...........832899775
..21....5536......940432.......174911750.........32001129185
..34...20569.....7558245......3077034244.......1229633337183
..55...76424....60744605.....54130248568......47247493674864
..89..283953...488197825....952245176313....1815445803499208
.144.1055026..3923590632..16751640356635...69756959373004005
.233.3919944.31533457665.294690365449276.2680352078247056300
LINKS
EXAMPLE
Some solutions for n=3 k=4 0=self 2=n 3=ne 4=w 6=e 7=sw 8=s (reciprocal directions total 10)
..8..8..0..7....0..6..4..0....0..0..6..4....6..4..7..0....0..0..0..0
..2..2..3..0....0..7..0..7....0..0..6..4....0..3..8..0....8..0..0..8
..0..0..6..4....3..0..3..0....0..0..6..4....0..0..2..0....2..6..4..2
CROSSREFS
Column 1 is A000045(n+1)
Sequence in context: A267644 A204197 A238654 * A176383 A100551 A267667
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin Dec 15 2012
STATUS
approved

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Last modified May 26 21:09 EDT 2024. Contains 372844 sequences. (Running on oeis4.)