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 #10 Aug 12 2016 06:54:17
%S 0,12,216,2700,54000,1054200,20991600,445365900,9628264800,
%T 212635396512,4790810344320,109495671909624,2534856710978592,
%U 59336480231336880,1402136110916757216,33409975384414912140,801962422581013417152
%N Number of 3 X n arrays containing n copies of 0..3-1 with row sums equal.
%C Row 3 of A268367.
%H R. H. Hardin, <a href="/A268369/b268369.txt">Table of n, a(n) for n = 1..40</a>
%F Conjecture: n^4*(1057*n^2 -3473*n +2902)*a(n) -(n-1) *(14798*n^5 -63420*n^4 +104199*n^3 -81821*n^2 +31698*n -4968)*a(n-1) +(-235711*n^6 +1717323*n^5 -5084885*n^4 +7773081*n^3 -6422772*n^2 +2716308*n -472176)*a(n-2) -96*(6*n -11) *(6*n-13) *(1057*n^2-1359*n+486) *(n-2)^2*a(n-3)=0. - _R. J. Mathar_, Feb 18 2016
%e Some solutions for n=5
%e ..1..1..1..0..2....0..0..2..2..1....1..0..2..1..1....0..1..2..0..2
%e ..0..1..0..2..2....1..1..1..2..0....1..0..2..0..2....0..1..1..1..2
%e ..0..0..2..2..1....0..1..2..0..2....0..0..2..1..2....2..0..0..1..2
%Y Cf. A268367.
%K nonn
%O 1,2
%A _R. H. Hardin_, Feb 03 2016