%I #12 Mar 28 2018 08:13:55
%S 1,9,23,51,175,513,1397,4133,12075,34521,100047,290287,838039,2423841,
%T 7016381,20290449,58686583,169784637,491117363,1420584719,4109370831,
%U 11887034385,34384871493,99464136973,287716480627,832264983105
%N Number of n X 6 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally.
%C Equivalent to all 1s connected only in 2 X 2 blocks.
%C Column 6 of A183342.
%H R. H. Hardin, <a href="/A183338/b183338.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = a(n1) + 2*a(n2) + 9*a(n3) + 6*a(n4)  3*a(n5)  10*a(n6)  17*a(n7)  7*a(n8) + 12*a(n9) + 12*a(n10)  6*a(n11).
%F Empirical g.f.: x*(1 + 8*x + 12*x^2 + x^3  9*x^4  22*x^5  26*x^6 + 5*x^7 + 24*x^8 + 6*x^9  6*x^10) / (1  x  2*x^2  9*x^3  6*x^4 + 3*x^5 + 10*x^6 + 17*x^7 + 7*x^8  12*x^9  12*x^10 + 6*x^11).  _Colin Barker_, Mar 27 2018
%e Some solutions for 5 X 6:
%e 0 0 0 0 1 1 0 0 0 0 0 0 1 1 0 0 1 1 0 1 1 0 1 1
%e 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 1 0 1 1
%e 1 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
%e 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 1 1 0
%e 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 1 1 0
%Y Cf. A183342.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 04 2011
