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A177649
Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down, up, down
0
1, 70, 31830, 50395146, 205822250572, 1808558575291438, 30242498188745996934
OFFSET
1,2
CROSSREFS
Sequence in context: A177642 A177644 A146499 * A177651 A177645 A177662
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved