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A190929
Number of permutations of n copies of 1..7 introduced in order 1..7 with no element equal to another within a distance of 3.
1
1, 4317, 27361381, 216956034178, 1979495929398725, 19864953170991117438, 213525202167474545255168, 2417277939494344003029244944, 28496810287352430019813986577684, 347046513903606031118705549409373406
OFFSET
1,2
LINKS
EXAMPLE
Some solutions for n=2
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
..2....2....2....2....2....2....2....2....2....2....2....2....2....2....2....2
..3....3....3....3....3....3....3....3....3....3....3....3....3....3....3....3
..4....4....4....4....4....4....4....4....4....4....4....4....4....4....4....4
..5....5....5....5....5....5....5....5....5....5....5....5....5....5....5....1
..1....6....6....6....1....6....1....6....6....1....1....1....6....6....6....5
..6....7....3....7....3....7....3....7....7....6....6....6....7....7....7....6
..7....4....2....2....6....4....2....3....3....7....2....7....3....4....4....7
..4....2....5....5....7....2....6....4....2....3....4....3....1....1....2....4
..2....1....7....3....2....5....7....5....6....2....7....4....4....2....1....5
..6....7....6....6....5....1....5....7....5....5....6....5....6....3....7....2
..3....5....1....1....4....6....4....6....1....7....3....7....2....5....3....7
..5....6....4....7....6....7....6....1....4....4....5....2....5....7....6....3
..7....3....7....4....7....3....7....2....7....6....7....6....7....6....5....6
CROSSREFS
Sequence in context: A210263 A165067 A236881 * A055153 A190011 A338537
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 23 2011
STATUS
approved