cp's OEIS Frontend

A260115 Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by eight: p(i)<>i and (i-p(i) mod n <= 8 or p(i)-i mod n <= 8).

%I A260115 #12 Jan 06 2016 13:53:56
%S A260115 1,0,1,2,9,44,265,1854,14833,133496,1334961,14684570,176214841,
%T A260115 2290792932,32071101049,481066515734,7697064251745,130850092279664,
%U A260115 817154768973824,5095853023109484,31742020729513344,197541094675490640,1228455950686697872,7634711586761705092
%N A260115 Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by eight: p(i)<>i and (i-p(i) mod n <= 8 or p(i)-i mod n <= 8).
%C A260115 a(n) = A000166(n) for n <= 17.
%p A260115 a:= n-> `if`(n=0, 1, LinearAlgebra[Permanent](Matrix(n, (i, j)->
%p A260115         `if`(i<>j and (i-j mod n<=8 or j-i mod n<=8), 1, 0)))):
%p A260115 seq(a(n), n=0..18);
%t A260115 a[n_] := If[n == 0, 1, Permanent[Table[If[i != j && (Mod[i - j, n] <= 8 || Mod[j - i, n] <= 8), 1, 0], {i, 1, n}, {j, 1, n}]]]; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 0, 18}] (* _Jean-François Alcover_, Jan 06 2016, adapted from Maple *)
%Y A260115 Cf. A000166, A260074, A260081, A260092, A260094, A260111, A260091, A257953, A260216.
%Y A260115 Cf. A259781.
%K A260115 nonn
%O A260115 0,4
%A A260115 _Alois P. Heinz_, Jul 16 2015