A186818 - OEIS

%I #5 Mar 31 2012 12:36:06

%S 606,3988,25808,173121,1190637,8178097,56422648,390661554,2704080467,

%T 18732156320,129837515003,899875661504,6237831734078,43243690039607,

%U 299782052613422,2078270386909730,14408014447228498,99886103229478687

%N Half the number of (n+2)X4 binary arrays with each 3X3 subblock having sum 4 or 5

%C Column 2 of A186825

%H R. H. Hardin, <a href="/A186818/b186818.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=5*a(n-1)+13*a(n-2)+80*a(n-3)-419*a(n-4)-760*a(n-5)-1400*a(n-6)+6108*a(n-7)+9112*a(n-8)+3844*a(n-9)-18505*a(n-10)-28582*a(n-11)+63966*a(n-12)-144930*a(n-13)+13184*a(n-14)-284223*a(n-15)+776448*a(n-16)-372906*a(n-17)-226710*a(n-18)+68796*a(n-19)+125280*a(n-20)+96552*a(n-21)-187272*a(n-22)+108864*a(n-23)+233280*a(n-24)-139968*a(n-25)

%e Some solutions for 6X4 with a(1,1)=0

%e ..0..1..0..0....0..0..1..1....0..0..1..1....0..0..1..1....0..0..1..1

%e ..0..1..1..0....1..0..1..1....1..0..1..0....0..0..0..1....1..1..0..0

%e ..0..1..1..0....0..0..1..0....0..0..1..0....1..1..1..0....0..1..0..1

%e ..0..0..0..1....0..1..1..0....1..0..1..1....0..1..0..1....1..1..0..0

%e ..1..0..1..0....0..1..0..0....0..0..1..0....0..0..0..0....1..0..1..1

%e ..1..1..1..1....1..0..0..1....0..1..0..0....1..1..1..0....0..1..0..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 27 2011