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A075852
Number of permutations s of {1,2,...,n} such that |s(i)-i|>3 for each i=1,2,...,n.
8
1, 0, 0, 0, 0, 0, 0, 0, 1, 16, 436, 6984, 114124, 1799688, 29125117, 486980182, 8490078104, 154750897552, 2951968964768, 58917663227568, 1229367602071416, 26787823838035750, 608794318333169289, 14411810690642972432
OFFSET
0,10
COMMENTS
a(n) equals the permanent of the n X n matrix with 0's along the main diagonal, the subdiagonal, the superdiagonal, the sub-subdiagonal, the super-superdiagonal, the sub-sub-subdiagonal, the super-super-superdiagonal, and 1's everywhere else. - John M. Campbell, Jul 09 2011
LINKS
George Spahn and Doron Zeilberger, Automatic Counting of Generalized Latin Rectangles and Trapezoids, arXiv:2108.11285 [math.CO], 2021.
MAPLE
b:= proc(s) option remember; (n-> `if`(n=0, 1, add(
`if`(abs(n-i)>3, b(s minus {i}), 0), i=s)))(nops(s))
end:
a:= n-> b({$1..n}):
seq(a(n), n=0..15); # Alois P. Heinz, Jan 25 2019
MATHEMATICA
a[0] = 1; a[n_] := a[n] = If[n < 8, 0, SparseArray[{Band[{1, 1}] -> 0, Band[{2, 1}] -> 0, Band[{3, 1}] -> 0, Band[{4, 1}] -> 0, Band[{1, 2}] -> 0, Band[{1, 3}] -> 0, Band[{1, 4}] -> 0}, {n, n}, 1] // Permanent];
Table[Print[n, " ", a[n]]; a[n], {n, 0, 23}] (* Jean-François Alcover, May 01 2019 *)
CROSSREFS
Sequence in context: A118994 A223686 A000489 * A260853 A068792 A229583
KEYWORD
nonn
AUTHOR
Reiner Martin, Oct 15 2002
EXTENSIONS
More terms from Vladimir Baltic, Vladeta Jovovic, Jan 04 2003
a(21) from Alois P. Heinz, Jul 04 2015
a(22)-a(23) from Alois P. Heinz, Jan 22 2019
a(0)=1 prepended by Alois P. Heinz, Jan 25 2019
STATUS
approved