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A177602
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up, down
0
1, 18, 1200, 196544, 64274760, 36903349792, 34074227986704, 47451264308831568
OFFSET
1,2
CROSSREFS
Sequence in context: A064564 A152933 A360602 * A252969 A182286 A292609
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved