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A211694
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Number of nonnegative integer arrays of length n+2*2-2 with new values introduced in order 0 upwards and every value appearing only in runs of at least 2
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3
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1, 2, 3, 6, 11, 23, 47, 103, 226, 518, 1200, 2867, 6946, 17234, 43393, 111419, 290242, 768901, 2065172, 5630083, 15549403, 43527487, 123343911, 353864422, 1026935904, 3014535166, 8945274505, 26829206798, 81293234754, 248805520401, 768882019073
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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G.f.: 1/x/W(0)-1/x, where W(k) = 1 - x - x^2/(1 - x^2*(k+1)/W(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Nov 10 2014
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EXAMPLE
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All solutions for n=5
..0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0
..0....0....1....0....1....0....0....0....1....1....1
..1....1....1....1....1....0....0....0....1....1....1
..1....1....2....1....1....0....1....0....0....1....1
..2....1....2....0....2....0....1....1....0....1....0
..2....1....2....0....2....0....1....1....0....1....0
G.f. = x + 2*x^2 + 3*x^3 + 6*x^4 + 11*x^5 + 23*x^6 + 47*x^7 + 103*x^8 + ...
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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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