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A251231
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Number of (n+1) X (3+1) 0..3 arrays with every 2 X 2 subblock summing to 6 and no 2 X 2 subblock having exactly two nonzero entries.
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1
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322, 694, 1592, 3886, 9914, 26224, 71322, 198318, 561212, 1611002, 4679574, 13730612, 40642206, 121238834, 364209520, 1101127798, 3348686298, 10239114144, 31464490330, 97136312190, 301153069996, 937321265322, 2927816428982
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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) = 13*a(n-1) -63*a(n-2) +122*a(n-3) +13*a(n-4) -371*a(n-5) +317*a(n-6) +308*a(n-7) -370*a(n-8) -144*a(n-9) +128*a(n-10) +48*a(n-11).
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EXAMPLE
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Some solutions for n=4:
..1..1..0..1....0..2..1..2....3..1..1..2....1..3..1..3....0..1..1..3
..1..3..2..3....2..2..1..2....1..1..3..0....1..1..1..1....3..2..2..0
..2..0..1..0....1..1..2..1....3..1..1..2....1..3..1..3....1..0..2..2
..1..3..2..3....3..1..2..1....0..2..2..1....1..1..1..1....3..2..2..0
..1..1..0..1....1..1..2..1....3..1..1..2....3..1..3..1....0..1..1..3
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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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