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

2,1

COMMENTS

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

LINKS

Table of n, a(n) for n=2..15.

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.

Sequence in context: A068679 A006978 A060424 * A220746 A110436 A126879

Adjacent sequences:  A119959 A119960 A119961 * A119963 A119964 A119965

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Aug 02 2006

STATUS

approved

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Last modified January 22 16:25 EST 2020. Contains 331152 sequences. (Running on oeis4.)