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A208642
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Number of 7 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.
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1
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64, 610, 2552, 7548, 18888, 43284, 94320, 199299, 412962, 844943, 1714680, 3461238, 6962956, 13976742, 28016664, 56111133, 112317270, 224749641, 449637728, 899440872, 1799078160, 3598388200, 7197048672, 14394415431, 28789200714
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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) = 8*a(n-1) - 27*a(n-2) + 50*a(n-3) - 55*a(n-4) + 36*a(n-5) - 13*a(n-6) + 2*a(n-7) for n>11.
G.f.: x*(64 + 98*x - 600*x^2 + 402*x^3 + 428*x^4 - 378*x^5 - 144*x^6 + 77*x^7 + 78*x^8 - 8*x^9 - 16*x^10) / ((1 - x)^6*(1 - 2*x)).
a(n) = (51480*(-3+2^(1+n)) - 71394*n - 13145*n^2 - 1205*n^3 - 55*n^4 - n^5) / 120 for n>4.
(End)
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EXAMPLE
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Some solutions for n=4:
..0..1..0..0....0..0..1..0....0..0..1..1....0..0..0..0....0..0..0..1
..1..0..1..1....1..0..1..0....1..0..0..0....1..1..1..0....1..1..0..1
..0..1..0..1....0..1..0..1....0..1..1..1....0..0..1..1....0..1..0..1
..1..0..1..0....1..0..1..0....0..0..0..0....1..0..0..1....1..0..1..0
..1..0..1..1....1..0..1..1....1..1..1..0....1..1..0..1....0..1..0..1
..1..0..0..0....0..1..0..1....0..0..1..1....0..1..0..0....0..1..0..0
..1..1..1..1....0..1..0..1....1..0..0..1....0..1..1..1....0..1..1..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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