cp's OEIS Frontend

A187856 Number of 8-step king-knight's tours (piece capable of both kinds of moves) on an n X n board summed over all starting positions.

%I A187856 #9 Jul 22 2025 10:55:25
%S A187856 0,0,49536,7067600,71450504,288493336,741624088,1474319716,2497432760,
%T A187856 3806665836,5395343360,7259273932,9396774760,11807403172,14491089616,
%U A187856 17447829164,20677621816,24180467572,27956366432,32005318396,36327323464
%N A187856 Number of 8-step king-knight's tours (piece capable of both kinds of moves) on an n X n board summed over all starting positions.
%C A187856 Row 8 of A187850
%H A187856 R. H. Hardin, <a href="/A187856/b187856.txt">Table of n, a(n) for n = 1..50</a>
%F A187856 Empirical: a(n) = 136526552*n^2 - 1275583564*n + 2906368876 for n>13
%e A187856 Some solutions for 3X3
%e A187856 ..8..5..2....0..8..4....5..4..3....8..4..6....0..4..7....8..4..5....8..4..1
%e A187856 ..7..6..1....3..7..1....8..2..6....5..3..7....5..2..8....2..0..7....7..2..3
%e A187856 ..4..3..0....6..5..2....0..1..7....0..1..2....1..6..3....1..6..3....5..6..0
%K A187856 nonn
%O A187856 1,3
%A A187856 _R. H. Hardin_ Mar 14 2011