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A206467
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Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having zero permanent.
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1
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441, 11025, 110889, 1896129, 23707161, 356190129, 4803737481, 69030731169, 955680252921, 13523866505361, 188928681187689, 2659384141993089, 37267791691450329, 523625523775949169, 7345838128808607561
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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) = 15*a(n-1) + 54*a(n-2) - 1116*a(n-3) + 1728*a(n-4) + 10368*a(n-5) - 20736*a(n-6).
Empirical g.f.: 9*x*(49 + 490*x - 8700*x^2 + 14400*x^3 + 91008*x^4 - 186624*x^5) / ((1 - 21*x + 108*x^2 - 144*x^3)*(1 + 6*x - 36*x^2 - 144*x^3)). - Colin Barker, Jun 16 2018
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EXAMPLE
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Some solutions for n=4:
2 2 2 1 2 2 0 0 0 1 0 1 1 2 0 0 0 0 2 0
0 0 0 0 0 0 0 1 0 2 0 2 0 0 0 2 0 0 2 0
1 2 1 0 2 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0
0 0 0 0 2 0 0 1 0 1 0 1 0 0 1 0 2 2 1 0
2 1 2 1 2 0 0 2 0 1 0 1 1 0 2 0 0 0 0 0
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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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