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%I #7 Jan 23 2019 07:14:53
%S 30,1206,11796,63420,242370,741090,1934856,4488696,9499590,18678990,
%T 34580700,60879156,102703146,167030010,263145360,403173360,602682606,
%U 881372646,1263846180,1780471980,2468343570,3372338706,4546284696
%N Number of length-7 0..n arrays with no repeated value equal to the previous repeated value.
%H R. H. Hardin, <a href="/A269471/b269471.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = n^7 + 7*n^6 + 16*n^5 + 8*n^4 - n^3 - n.
%F Conjectures from _Colin Barker_, Jan 23 2019: (Start)
%F G.f.: 6*x*(5 + 161*x + 498*x^2 + 190*x^3 - 23*x^4 + 9*x^5) /(1 - x)^8.
%F a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.
%F (End)
%e Some solutions for n=3:
%e ..2. .0. .0. .0. .1. .1. .0. .0. .0. .1. .3. .0. .2. .3. .3. .0
%e ..0. .2. .2. .3. .2. .3. .1. .2. .2. .2. .2. .1. .1. .3. .3. .1
%e ..2. .2. .1. .0. .2. .1. .3. .2. .2. .2. .3. .0. .1. .1. .0. .3
%e ..3. .0. .2. .3. .0. .2. .2. .0. .3. .3. .0. .2. .3. .0. .1. .0
%e ..1. .1. .3. .2. .0. .3. .2. .0. .3. .2. .1. .2. .2. .2. .1. .0
%e ..0. .1. .2. .0. .2. .3. .0. .1. .2. .3. .3. .3. .2. .1. .2. .3
%e ..3. .2. .3. .1. .1. .2. .0. .0. .1. .1. .2. .1. .3. .3. .2. .3
%Y Row 7 of A269467.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 27 2016
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