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 A111936 Denominator of n-th term of the harmonic series after having removed all terms containing in decimal representation a 9. 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numerator = A111935; A111935(n)/a(n) ---> C with C<80. REFERENCES G. Polya and G. Szego, Problems and Theorems in Analysis I (Springer 1924, reprinted 1972), Part One, Chap. 3, sect. 4, Problem 124. LINKS EXAMPLE 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. MATHEMATICA Denominator[Accumulate[DeleteCases[Table[1/n, {n, 40}], _?(MemberQ[ IntegerDigits[ Denominator[#]], 9]&)]]] (* Harvey P. Dale, Mar 05 2013 *) CROSSREFS Cf. A002805, A007095. Sequence in context: A175810 A083001 A119862 * A203811 A002805 A117481 Adjacent sequences:  A111933 A111934 A111935 * A111937 A111938 A111939 KEYWORD nonn,base,frac AUTHOR Reinhard Zumkeller, Aug 22 2005 STATUS approved

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