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A174077
Number of permutations of length n with no consecutive triples i,i+2,i+4 (mod n) or i,i-2,i-4 (mod n).
3
1, 1, 2, 0, 24, 80, 504, 3794, 31616, 290970, 2973600, 33311520, 405781344, 5342413414, 75612197528, 1144942063230, 18471128518656, 316309310084728, 5730646943736936
OFFSET
0,3
EXAMPLE
As an example, (0,4,1,2,3) is counted by a(5), but (0,4,1,3,2) is not because it has the progression 4,1,3.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Isaac Lambert, Mar 10 2010
EXTENSIONS
Definition corrected by Isaac Lambert, Mar 15 2010
a(0)-a(4) and a(10)-a(18) from Alois P. Heinz, Apr 15 2021
STATUS
approved