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 A075851 Number of permutations s of {1,2,...,n} such that |s(i)-i|>2 for each i=1,2,...,n. 8
 1, 0, 0, 0, 0, 0, 1, 8, 112, 1168, 13365, 159414, 2036488, 27780408, 404351752, 6263006598, 102946702825, 1790795492176, 32880327473840, 635630231970048, 12907624693811937, 274744151265431700, 6117666413618771968, 142238172767973342656 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 COMMENTS a(n) equals the permanent of the n X n matrix with 0's along the main diagonal, the superdiagonal, the subdiagonal, the sub-subdiagonal, the super-superdiagonal, and 1's everywhere else. - John M. Campbell, Jul 09 2011 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..450 MAPLE b:= proc(s) option remember; (n-> `if`(n=0, 1, add(       `if`(abs(n-i)>2, 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<6, 0, SparseArray[{Band[{1, 1}] -> 0, Band[{2, 1}] -> 0, Band[{3, 1}] -> 0, Band[{1, 2}] -> 0, Band[{1, 3}] -> 0}, {n, n}, 1] // Permanent]; Table[Print[n, " ", a[n]]; a[n], {n, 0, 23}] (* Jean-François Alcover, Apr 30 2019 *) CROSSREFS Cf. A001883, A075852. Sequence in context: A317000 A316818 A317568 * A270111 A053536 A139741 Adjacent sequences:  A075848 A075849 A075850 * A075852 A075853 A075854 KEYWORD nonn AUTHOR Reiner Martin (reinermartin(AT)hotmail.com), 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

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Last modified May 27 08:12 EDT 2022. Contains 354096 sequences. (Running on oeis4.)