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%I #7 Jan 23 2019 07:12:07
%S 22,462,3180,13300,41730,108402,246232,505800,960750,1713910,2904132,
%T 4713852,7377370,11189850,16517040,23805712,33594822,46527390,
%U 63363100,84991620,112446642,146920642,189780360,242583000,307093150,385300422
%N Number of length-6 0..n arrays with no repeated value equal to the previous repeated value.
%H R. H. Hardin, <a href="/A269470/b269470.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = n^6 + 6*n^5 + 11*n^4 + 4*n^3 - n^2 + n.
%F Conjectures from _Colin Barker_, Jan 23 2019: (Start)
%F G.f.: 2*x*(11 + 154*x + 204*x^2 - 14*x^3 + 5*x^4) / (1 - x)^7.
%F a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.
%F (End)
%e Some solutions for n=3:
%e ..1. .2. .1. .2. .1. .2. .1. .0. .1. .3. .1. .0. .3. .0. .3. .2
%e ..0. .3. .0. .1. .0. .0. .0. .3. .3. .0. .1. .2. .0. .2. .2. .1
%e ..3. .3. .1. .2. .2. .1. .0. .0. .3. .1. .3. .1. .1. .0. .0. .0
%e ..0. .1. .3. .2. .1. .3. .2. .3. .0. .0. .2. .1. .1. .3. .1. .1
%e ..2. .1. .2. .0. .3. .1. .0. .2. .0. .0. .2. .3. .0. .2. .0. .0
%e ..2. .0. .1. .0. .1. .2. .2. .3. .2. .1. .3. .3. .1. .2. .0. .2
%Y Row 6 of A269467.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 27 2016
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