%I #7 Jan 25 2019 09:28:34
%S 4,16,60,221,796,2828,9928,34537,119236,409098,1396288,4744671,
%T 16062116,54199810,182382428,612236251,2050883956,6857469364,
%U 22892085300,76311433969,254067536796,844941922160,2807225267056,9318543171653
%N Number of lengthn 0..3 arrays with no repeated value differing from the previous repeated value by other than plus two or minus 1.
%H R. H. Hardin, <a href="/A269635/b269635.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 9*a(n1)  21*a(n2)  19*a(n3) + 93*a(n4) + 27*a(n5)  133*a(n6)  87*a(n7).
%F Empirical g.f.: x*(4  20*x + 93*x^3  x^4  151*x^5  89*x^6) / ((1  3*x)*(1  6*x + 3*x^2 + 28*x^3  9*x^4  54*x^5  29*x^6)).  _Colin Barker_, Jan 25 2019
%e Some solutions for n=9:
%e ..2. .1. .2. .1. .2. .0. .2. .1. .1. .1. .1. .3. .3. .0. .0. .2
%e ..0. .2. .3. .3. .2. .1. .0. .3. .3. .2. .3. .0. .1. .2. .2. .0
%e ..3. .0. .0. .0. .1. .3. .0. .2. .2. .2. .0. .1. .3. .0. .1. .3
%e ..1. .3. .2. .1. .0. .2. .1. .3. .1. .0. .3. .1. .0. .1. .3. .1
%e ..0. .0. .2. .1. .3. .0. .0. .2. .3. .2. .1. .0. .3. .2. .0. .2
%e ..1. .1. .0. .2. .2. .2. .2. .0. .2. .3. .2. .3. .0. .1. .3. .3
%e ..3. .3. .3. .0. .3. .3. .2. .1. .0. .1. .0. .2. .0. .2. .2. .1
%e ..0. .3. .2. .1. .1. .2. .1. .2. .1. .3. .2. .0. .2. .3. .0. .0
%e ..0. .0. .0. .0. .2. .0. .3. .1. .0. .1. .2. .2. .0. .2. .3. .2
%Y Column 3 of A269640.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 02 2016
