cp's OEIS Frontend

A186856 Number of 7-step knight's tours on an (n+2) X (n+2) board summed over all starting positions.

%I A186856 #13 Jan 02 2023 21:57:01
%S A186856 16,1280,21664,118480,372384,847520,1584576,2596480,3879696,5424848,
%T A186856 7224912,9277856,11583680,14142384,16953968,20018432,23335776,
%U A186856 26906000,30729104,34805088,39133952,43715696,48550320,53637824,58978208,64571472
%N A186856 Number of 7-step knight's tours on an (n+2) X (n+2) board summed over all starting positions.
%H A186856 Andrew Howroyd, <a href="/A186856/b186856.txt">Table of n, a(n) for n = 1..1000</a>
%F A186856 a(n) = 126440*n^2 - 855176*n + 1332608 for n >= 10. - _Andrew Howroyd_, Jan 02 2023
%e A186856 Some solutions for 5 X 5:
%e A186856   0 1 0 0 0     2 0 0 0 0     0 0 0 1 0     2 0 0 0 0
%e A186856   0 0 0 0 0     0 0 3 0 0     3 6 0 0 0     0 0 1 0 0
%e A186856   0 5 2 0 0     0 1 6 0 0     0 0 2 5 0     0 3 6 0 0
%e A186856   7 0 0 4 0     0 4 0 0 0     0 4 7 0 0     0 0 0 4 7
%e A186856   0 3 6 0 0     0 7 0 5 0     0 0 0 0 0     0 5 0 0 0
%o A186856 (PARI) row(7, 30) \\ row(m,n) defined in A186851. - _Andrew Howroyd_, Jan 02 2023
%Y A186856 Row 7 of A186851.
%K A186856 nonn
%O A186856 1,1
%A A186856 _R. H. Hardin_, Feb 27 2011
%E A186856 Terms a(11) and beyond from _Andrew Howroyd_, Jan 02 2023