%I #4 Dec 18 2015 18:17:24
%S 1,104,6549,492920,63388030
%N Number of n X n 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, 4 in the lower right corner, and with no element having more than 3 neighbors with the same value
%e Some solutions for n=4
%e ...1.1.2.2...1.4.4.2...1.1.3.2...1.1.2.2...1.1.2.2...1.1.2.2...1.1.1.2
%e ...3.1.2.4...1.1.4.2...1.1.3.2...3.1.2.2...1.1.2.2...1.3.2.2...1.3.1.2
%e ...3.3.2.4...1.3.4.2...3.3.3.2...3.1.2.4...1.4.4.2...3.3.3.4...3.3.1.2
%e ...3.3.4.4...3.3.4.4...3.3.4.4...3.1.2.4...3.3.4.4...3.4.4.4...3.1.1.4
%e ------
%e ...1.2.2.2...1.4.4.2...1.2.2.2...1.2.2.2...1.1.2.2...1.2.2.2...1.1.2.2
%e ...1.2.3.2...1.4.4.2...1.3.2.2...1.1.2.4...1.3.3.2...1.1.1.1...1.2.2.2
%e ...3.3.3.3...3.4.4.2...3.3.2.2...1.3.4.4...1.3.3.3...3.1.1.4...1.2.4.4
%e ...3.4.4.4...3.3.4.4...3.3.2.4...3.3.3.4...3.3.4.4...3.3.4.4...3.2.4.4
%K nonn
%O 2,2
%A _R. H. Hardin_ Aug 24 2009
|