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A177666
Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, up, down, up, down
0
1, 68, 31212, 50966304, 217643900486, 2016891757663928, 35773214436504563352
OFFSET
1,2
CROSSREFS
Sequence in context: A307137 A230685 A093234 * A292607 A211311 A367529
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved