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A208000
Number of nX4 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any knight-move neighbor (colorings ignoring permutations of colors).
2
15, 1657, 426422, 450288795, 1182700979380, 6184248124218800, 56513375910372605548, 826725568737937330039810, 18171823971396715681105965282, 572057633247843506849301892746850, 24840621984533068280588275487942834483, 1443495070617319156132945205013820325621405
OFFSET
1,1
LINKS
EXAMPLE
Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..1..1..1..1....1..1..1..1....1..1..1..1....1..1..1..2....1..1..1..1
..2..2..2..3....2..2..2..2....2..2..2..2....2..1..2..2....2..2..2..2
..0..0..0..0....0..0..0..0....3..3..0..0....0..0..3..4....0..0..3..0
CROSSREFS
Column 4 of A208001.
Sequence in context: A209683 A249964 A281801 * A182925 A208020 A205423
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 22 2012
EXTENSIONS
Terms a(6) and beyond from Andrew Howroyd, Jul 01 2017
STATUS
approved