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A125707 Numbers n such that A024528(n) is prime. 1
1, 2, 3, 4, 5, 7, 14, 15, 17, 23, 32, 36, 42, 309, 1384, 1588 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A024528(n) is the numerator of 1 + Sum[ 1/Prime[k], {k,1,n} ], or n-th elementary symmetric function of {1, prime(1), prime(2), ..., prime(n-1)}.

LINKS

Table of n, a(n) for n=1..16.

MATHEMATICA

f=1; Do[p=Prime[n]; f=f+1/p; g=Numerator[f]; If[PrimeQ[g], Print[{n, p, g}]], {n, 1, 50}]

CROSSREFS

Cf. A024528, A109628.

Sequence in context: A066661 A268199 A178767 * A039060 A278442 A092065

Adjacent sequences:  A125704 A125705 A125706 * A125708 A125709 A125710

KEYWORD

hard,more,nonn

AUTHOR

Alexander Adamchuk, Feb 01 2007

EXTENSIONS

3 more terms from Ryan Propper, Feb 11 2008

STATUS

approved

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Last modified January 16 03:17 EST 2019. Contains 319184 sequences. (Running on oeis4.)