%I #9 Aug 16 2018 08:58:49
%S 1,2,3,7,20,67,255,1079,4987,24759,129947,710791,4004619,23031191,
%T 134328379,790907943,4686298091,27884452663,166383085851,994632987335,
%U 5953222496203,35661292725975,213736364551163,1281494949329767
%N Number of n X 1 0..6 arrays with no element equal to another at a city block distance of exactly two, and new values 0..6 introduced in row major order.
%C Column 1 of A222779.
%H R. H. Hardin, <a href="/A222776/b222776.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 16*a(n-1) - 95*a(n-2) + 260*a(n-3) - 324*a(n-4) + 144*a(n-5) for n>7.
%F Empirical g.f.: x*(1 + x)*(1 - 15*x + 81*x^2 - 192*x^3 + 189*x^4 - 53*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 6*x)). - _Colin Barker_, Aug 16 2018
%e All solutions for n=3:
%e ..0....0....0
%e ..1....1....0
%e ..2....1....1
%Y Cf. A222779.
%K nonn
%O 1,2
%A _R. H. Hardin_, Mar 05 2013