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A211109 1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having two, three or four distinct values 1

%I

%S 15,891,208575,192515373,700590250755,10052185332068649,

%T 568662258529219221297,126836971252795362522842613,

%U 111541083171262765512515480985165

%N 1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having two, three or four distinct values

%H R. H. Hardin, <a href="/A211109/b211109.txt">Table of n, a(n) for n = 1..15</a>

%e Some solutions for n=3

%e ..2..2..3..1....2..2..1..3....0..0..0..0....0..0..1..2....2..0..3..1

%e ..2..0..0..1....2..0..1..3....0..2..2..0....0..2..1..3....0..2..3..0

%e ..3..0..1..2....1..1..1..0....0..2..1..2....1..1..3..2....3..3..0..2

%e ..1..1..2..1....3..3..0..1....0..0..2..3....2..3..2..3....1..0..2..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 31 2012

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Last modified October 17 21:17 EDT 2021. Contains 348065 sequences. (Running on oeis4.)