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%I #8 Sep 01 2018 09:17:56
%S 990,611,728,861,974,1233,1614,2099,2665,3459,4600,6193,8316,11198,
%T 15183,20724,28348,38815,53225,73135,100625,138539,190817,262960,
%U 362545,499997,689677,951451,1312758,1811466,2499800,3449855,4761161,6571120,9069355
%N Number of (n+3) X 8 0..1 matrices with each 4 X 4 subblock idempotent.
%C Column 5 of A224568.
%H R. H. Hardin, <a href="/A224565/b224565.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 4*a(n-4) - 3*a(n-5) + 2*a(n-7) - a(n-8) for n>10.
%F Empirical g.f.: x*(990 - 2359*x + 875*x^2 + 1879*x^3 - 2891*x^4 + 2015*x^5 + 506*x^6 - 1569*x^7 + 517*x^8 + 35*x^9) / ((1 - x)^3*(1 + x)*(1 - x - x^4)). - _Colin Barker_, Sep 01 2018
%e Some solutions for n=3:
%e ..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....1..1..1..1..1..0..1..1
%e ..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0
%e ..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0
%e ..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0
%e ..1..0..0..0..0..0..1..0....1..0..1..1..1..1..1..1....0..0..0..0..0..0..0..0
%e ..0..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..1..1
%Y Cf. A224568.
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 10 2013
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