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A260094
Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by five: p(i)<>i and (i-p(i) mod n <= 5 or p(i)-i mod n <= 5).
9
1, 0, 1, 2, 9, 44, 265, 1854, 14833, 133496, 1334961, 14684570, 59245120, 238282730, 956135652, 3828509472, 15296722436, 60990443730, 243596762752, 975165838970, 3913571754304, 15742403448024, 63428117376852, 255662480209770, 1031080275942464, 4161127398011040
OFFSET
0,4
COMMENTS
a(n) = A000166(n) for n <= 11.
MAPLE
a:= n-> `if`(n=0, 1, LinearAlgebra[Permanent](Matrix(n, (i, j)->
`if`(i<>j and (i-j mod n<=5 or j-i mod n<=5), 1, 0)))):
seq(a(n), n=0..15);
MATHEMATICA
a[n_] := If[n == 0, 1, Permanent[Table[If[i != j && (Mod[i - j, n] <= 5 || Mod[j - i, n] <= 5), 1, 0], {i, 1, n}, {j, 1, n}]]]; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 0, 15}] (* Jean-François Alcover, Jan 06 2016, adapted from Maple *)
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 15 2015
STATUS
approved