Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #3 Mar 31 2012 12:35:35
%S 13,0,11588,110364,4185118,113675050,3445935988
%N Number of slanted 8Xn (i=1..8)X(j=i..n+i-1) 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 One solution for n=7
%e ...1.1.2.2.2.2.2..............
%e .....1.1.1.1.2.2.2............
%e .......2.2.2.2.3.2.3..........
%e .........2.2.3.3.2.3.3........
%e ...........2.3.3.2.3.3.4......
%e .............3.3.2.3.4.4.4....
%e ...............3.3.3.3.3.4.4..
%e .................3.4.4.4.4.4.4
%K nonn
%O 2,1
%A _R. H. Hardin_ Sep 17 2009