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%I #8 Sep 03 2018 11:37:31
%S 4405,1938,2136,2429,2700,2926,3540,4514,5773,7247,8885,11074,14173,
%T 18466,24167,31439,40832,53255,69901,92177,121653,160449,211594,
%U 279310,369226,488541,646574,855673,1132408,1498978,1984781,2628534,3481302
%N Number of (n+4) X 9 0..1 matrices with each 5 X 5 subblock idempotent.
%H R. H. Hardin, <a href="/A224687/b224687.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + a(n-5) - 3*a(n-6) + 3*a(n-7) - a(n-8) for n>12.
%F Empirical g.f.: x*(4405 - 15682*x + 20814*x^2 - 12107*x^3 + 2453*x^4 - 4311*x^5 + 11733*x^6 - 9998*x^7 + 2523*x^8 + 122*x^9 + 42*x^10 + 5*x^11) / ((1 - x)^3*(1 - x + x^2)*(1 - x^2 - x^3)). - _Colin Barker_, Sep 03 2018
%e Some solutions for n=2:
%e ..1..1..1..1..1..0..0..1..1....1..0..0..0..0..0..0..0..0
%e ..0..0..0..0..0..0..0..0..0....1..0..0..0..0..0..0..0..0
%e ..0..0..0..0..0..0..0..0..0....0..0..1..0..1..0..1..0..0
%e ..0..0..0..0..0..0..0..0..0....0..0..1..0..1..0..1..0..0
%e ..0..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0..0
%e ..1..0..0..1..1..1..1..1..1....0..0..0..0..0..0..0..0..1
%Y Column 5 of A224690.
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 15 2013
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