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A111936
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Denominator of n-th term of the harmonic series after having removed all terms containing in decimal representation a 9.
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1
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1, 2, 6, 12, 60, 20, 140, 280, 280, 3080, 9240, 120120, 120120, 40040, 80080, 1361360, 12252240, 2450448, 2450448, 2450448, 56360304, 56360304, 1409007600, 1409007600, 4227022800, 4227022800, 4227022800, 131037706800, 262075413600
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OFFSET
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1,2
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COMMENTS
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Numerator = A111935;
A111935(n)/a(n) ---> C with C<80.
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REFERENCES
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G. Polya and G. Szego, Problems and Theorems in Analysis I (Springer 1924, reprinted 1972), Part One, Chap. 3, sect. 4, Problem 124.
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LINKS
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Table of n, a(n) for n=1..29.
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EXAMPLE
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n=9: 1/1+1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/10 = 789/280, therefore a(9) = 280.
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MATHEMATICA
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Denominator[Accumulate[DeleteCases[Table[1/n, {n, 40}], _?(MemberQ[ IntegerDigits[ Denominator[#]], 9]&)]]] (* Harvey P. Dale, Mar 05 2013 *)
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CROSSREFS
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Cf. A002805, A007095.
Sequence in context: A175810 A083001 A119862 * A203811 A002805 A117481
Adjacent sequences: A111933 A111934 A111935 * A111937 A111938 A111939
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KEYWORD
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nonn,base,frac
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AUTHOR
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Reinhard Zumkeller, Aug 22 2005
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STATUS
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approved
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