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A324514
Number of aperiodic permutations of {1..n}.
7
1, 0, 3, 16, 115, 660, 5033, 39936, 362718, 3624920, 39916789, 478953648, 6227020787, 87177645996, 1307674338105, 20922779566080, 355687428095983, 6402373519409856, 121645100408831981, 2432902004460734000, 51090942171698415483, 1124000727695858073380
OFFSET
1,3
COMMENTS
A permutation is defined to be aperiodic if every cyclic rotation of {1..n} acts on the cycle decomposition to produce a different digraph.
FORMULA
a(n) = A306669(n) * n.
a(n) = Sum_{d|n} mu(n/d)*(n/d)^d*d!. - Andrew Howroyd, Aug 19 2019
EXAMPLE
The a(4) = 16 aperiodic permutations:
(1243) (1324) (1342) (1423)
(2134) (2314) (2413) (2431)
(3124) (3142) (3241) (3421)
(4132) (4213) (4231) (4312)
MATHEMATICA
Table[Length[Select[Permutations[Range[n]], UnsameQ@@NestList[RotateRight[#/.k_Integer:>If[k==n, 1, k+1]]&, #, n-1]&]], {n, 6}]
PROG
(PARI) a(n) = sumdiv(n, d, moebius(n/d)*(n/d)^d*d!); \\ Andrew Howroyd, Aug 19 2019
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 04 2019
EXTENSIONS
Terms a(10) and beyond from Andrew Howroyd, Aug 19 2019
STATUS
approved