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A119962 Largest prime factor of the odd denominator of n * n-th harmonic number = A027611[2^n]. +0
1
3, 7, 13, 31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381, 32749 (list; graph; listen)
OFFSET

2,1

COMMENT

It appears that a(n) = A014234[n] for n>1.

FORMULA

a(n) = Max[ FactorInteger[ Denominator[ 2^n * Sum[1/k, {k,1,2^n} ]]]].

MATHEMATICA

Table[Max[Flatten[FactorInteger[Denominator[2^n*Sum[1/k, {k, 1, 2^n}]]]]], {n, 2, 15}]

CROSSREFS

Cf. A119526, A027611, A014234.

Adjacent sequences: A119959 A119960 A119961 this_sequence A119963 A119964 A119965

Sequence in context: A068679 A006978 A060424 this_sequence A110436 A126879 A077314

KEYWORD

nonn

AUTHOR

Alexander Adamchuk (alex(AT)kolmogorov.com), Aug 02 2006

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.


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