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Number of length-n 0..n arrays with no repeated value equal to the previous repeated value.
1

%I #5 Feb 27 2016 10:24:26

%S 2,9,60,580,7170,108402,1934856,39808584,927352710,24123618310,

%T 693066874236,21793557008028,744461976979994,27451268150267850,

%U 1086741065393740560,45971289976043485456,2069440771476789080334

%N Number of length-n 0..n arrays with no repeated value equal to the previous repeated value.

%C Diagonal of A269467.

%H R. H. Hardin, <a href="/A269460/b269460.txt">Table of n, a(n) for n = 1..193</a>

%e Some solutions for n=6

%e ..2. .5. .2. .3. .4. .0. .4. .2. .6. .5. .0. .0. .1. .6. .4. .5

%e ..0. .2. .0. .6. .4. .6. .6. .3. .3. .3. .3. .3. .5. .4. .6. .1

%e ..0. .3. .2. .2. .3. .3. .0. .3. .5. .6. .6. .5. .5. .2. .3. .5

%e ..2. .6. .1. .6. .5. .5. .5. .6. .5. .4. .3. .1. .2. .2. .5. .0

%e ..2. .3. .5. .2. .3. .6. .0. .5. .6. .1. .4. .0. .2. .6. .4. .1

%e ..6. .1. .5. .4. .2. .2. .0. .1. .3. .2. .3. .3. .3. .3. .4. .5

%Y Cf. A269467.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 27 2016