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A174081
Number of permutations of length n with no consecutive triples i,i+d,i+2d (mod n) for all d.
3
16, 40, 300, 1764, 17056, 118908
OFFSET
4,1
EXAMPLE
For n=4, there are 4!-a(4)=8 permutations with some consecutive triple i,i+d,i+2d (mod 4). Here only d=1 and d=3 works, and the permutations are (0,1,2,3), (1,2,3,0), (2,3,0,1), (3,0,1,2), (0,3,2,1), (3,2,1,0), (2,1,0,3), and (1,0,3,2)
CROSSREFS
KEYWORD
nonn
AUTHOR
Isaac Lambert, Mar 15 2010
STATUS
approved