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A261882
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Decimal expansion of 32/27.
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0
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1, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5, 1, 8, 5
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OFFSET
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1,3
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COMMENTS
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For any number x >= 32/27 and any e > 0, there is a graph G such that the chromatic polynomial of G has a real root between x - e and x + e. (All real roots of such polynomials are 0, 1, or in this range.)
Continued fraction expansion of (sqrt(730)-10)/9. - Bruno Berselli, Sep 04 2015
Equals the ratio of the wavelengths between the hydrogen spectral lines Lyman-alpha (121.6 nm) and Lyman-beta (102.6 nm). - Sean Stroud, Apr 15 2019
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LINKS
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FORMULA
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G.f.: x*(1 + x + 8*x^2 + 4*x^3)/((1 - x)*(1 + x + x^2)). - Bruno Berselli, Sep 04 2015
a(n) = 7-(-1)^(n-1 mod 3)/2-5*(-1)^(n mod 3)/2-4*(-1)^(n+1 mod 3), n>1. - Wesley Ivan Hurt, Sep 04 2015
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EXAMPLE
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1.18518518518518518...
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MAPLE
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MATHEMATICA
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Join[{1}, Table[7 - (-1)^Mod[n - 1, 3]/2 - 5 (-1)^Mod[n, 3]/2 - 4 (-1)^Mod[n + 1, 3], {n, 2, 40}]] (* Wesley Ivan Hurt, Sep 04 2015 *)
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PROG
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(PARI) 32/27.
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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