cp's OEIS Frontend

A187195 Number of 8-turn rook's tours on an n X n board summed over all starting positions.

%I A187195 #14 Apr 19 2022 07:38:33
%S A187195 0,0,2664,551232,12319200,118332000,709921800,3141298944,11217854592,
%T A187195 34149988800,91867386600,223898241600
%N A187195 Number of 8-turn rook's tours on an n X n board summed over all starting positions.
%F A187195 Empirical: a(n) = 128*n^9 - 1538*n^8 + 7956*n^7 - 23556*n^6 + 44586*n^5 - 55218*n^4 + 40894*n^3 - 13252*n^2.
%F A187195 Empirical G.f.: 72*x^3 * (2599*x^6 +52838*x^5 +213575*x^4 +272580*x^3 +96205*x^2 +7286*x +37) / (x-1)^10. [_Colin Barker_, Jul 01 2012]
%e A187195 Some solutions for 4X4
%e A187195 ..4..2..3..0....0..6..7..5....0..5..0..6....0..2..3..0....2..8..3..0
%e A187195 ..5..0..0..8....0..0..0..0....8..0..0..7....7..1..6..8....1..6..5..0
%e A187195 ..0..1..0..0....0..1..2..3....0..0..1..0....0..0..5..0....0..7..0..0
%e A187195 ..6..0..0..7....0..0..8..4....0..4..2..3....0..0..4..0....0..0..4..0
%Y A187195 Row 8 of A187189.
%K A187195 nonn,more
%O A187195 1,3
%A A187195 _R. H. Hardin_, Mar 06 2011