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A177641
Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down, down.
0
1, 70, 34650, 59789280, 266337847482, 2554877633330088, 46673357620120575102, 1485635287258589886509256
OFFSET
1,2
CROSSREFS
Sequence in context: A177299 A266740 A177640 * A177648 A177653 A177659
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 10 2010
EXTENSIONS
a(8) from Alois P. Heinz, Nov 02 2013
STATUS
approved