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 A119788 Ratio of the numerator of the product of n and the n-th alternating harmonic number n*H'(n) to the numerator of the n-th alternating harmonic number H'(n) = Sum_{k=1..n} (-1)^(k+1)*1/k. 4
 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,15 COMMENTS Indices n such that a(n) is not equal to 1 are listed in A121594. It appears that most a(n) > 1 are a prime divisor of their corresponding indices A121594(n). The first and only composite term up to a(6000) is a(1470) = 49 that also divides its index. A compressed version of this sequence (all 1 entries are excluded) is A121595. LINKS Alexander Adamchuk, Table of n, a(n) for n = 1..400 FORMULA a(n) = numerator(n*Sum_{i=1..n} (-1)^(i+1)*1/i) / numerator(Sum_{i=1..n}(-1)^(i+1)*1/i). a(n) = A119787(n) / A058313(n). MATHEMATICA Numerator[Table[n*Sum[(-1)^(i+1)*1/i, {i, 1, n}], {n, 1, 600}]]/Numerator[Table[Sum[(-1)^(i+1)*1/i, {i, 1, n}], {n, 1, 600}]] CROSSREFS Cf. A058313, A092579, A119787, A121594, A121595. Sequence in context: A257098 A322356 A337337 * A334561 A059592 A295554 Adjacent sequences:  A119785 A119786 A119787 * A119789 A119790 A119791 KEYWORD frac,nonn AUTHOR Alexander Adamchuk, Jun 26 2006, Sep 21 2006 STATUS approved

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Last modified August 3 22:03 EDT 2021. Contains 346441 sequences. (Running on oeis4.)