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A177648
Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down, down, up
0
1, 70, 34650, 60778746, 277113842057, 2730472552564105, 51347486465256186884
OFFSET
1,2
CROSSREFS
Sequence in context: A266740 A177640 A177641 * A177653 A177659 A177665
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved