A164750 - OEIS

%I #4 Mar 31 2012 12:35:35

%S 33,730,8181,66970,454001,2710440,14765875,75078360,361767973,

%T 1669896490,7442607455,32219919102,136108600539,563096090012,

%U 2288108822659,9153641479832,36122611753603,140843294581018,543321531506705

%N Number of nX4 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, and 4 in the lower right corner

%H R. H. Hardin, <a href="/A164750/b164750.txt">Table of n, a(n) for n=2..21</a>

%e Some solutions for n=3

%e ...1.3.3.2...1.1.2.2...1.2.2.2...1.3.3.2...1.2.2.2...1.1.1.2...1.1.1.2

%e ...1.3.4.2...1.1.2.4...2.2.2.4...1.1.3.2...1.2.2.4...1.3.3.4...1.3.3.4

%e ...3.3.4.4...3.1.1.4...3.3.2.4...3.3.3.4...3.3.4.4...3.3.3.4...3.3.4.4

%e ------

%e ...1.1.1.2...1.1.2.2...1.1.1.2...1.1.2.2...1.1.1.2...1.1.1.2...1.1.3.2

%e ...3.3.2.2...3.1.2.4...4.4.4.4...1.1.1.1...1.3.1.2...1.3.1.4...3.1.3.2

%e ...3.4.4.4...3.4.4.4...3.3.4.4...3.3.1.4...3.3.1.4...3.3.1.4...3.3.3.4

%K nonn

%O 2,1

%A _R. H. Hardin_ Aug 24 2009