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A177645
Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, up, down, down
0
1, 70, 32988, 53577384, 223138602958, 1992266686369568, 33770993367805159464
OFFSET
1,2
CROSSREFS
Sequence in context: A146499 A177649 A177651 * A177662 A177669 A177667
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved