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A224674
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Number of (n+1) X 7 0..2 matrices with each 2 X 2 subblock idempotent.
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1
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189, 300, 398, 573, 793, 1126, 1608, 2343, 3471, 5236, 8022, 12457, 19553, 30950, 49300, 78895, 126679, 203888, 328702, 530537, 856989, 1385070, 2239388, 3621563, 5857823, 9476016, 15330218, 24802353, 40128421, 64926346, 105050052, 169971387
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5) for n > 6.
Empirical g.f.: x*(189 - 456*x + 143*x^2 + 292*x^3 - 187*x^4 + 10*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Feb 17 2018
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EXAMPLE
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Some solutions for n=3:
1 0 1 0 1 0 2 1 1 1 1 1 1 2 0 0 0 0 1 0 0
1 0 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 1
0 0 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 1
0 0 1 0 1 0 1 2 1 1 1 1 1 1 0 0 0 0 1 0 1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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