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A074631 Sum of a(n) terms of Composite-Harmonic series, Sum 1/(i-th composite), is > n. 5
9, 44, 168, 587, 1940, 6192, 19285, 59010, 178122, 531923, 1574706, 4628338, 13521477, 39299115, 113712434, 327752962, 941457955 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..17.

FORMULA

Lim as n -> inf. a(n+1)/a(n) = e. - Robert G. Wilson v, Aug 28 2002

EXAMPLE

1/4 +1/6 +1/8 +1/9 +1/10 +1/12 +1/14 +1/15 +1/16 = 1045/1008, but if 1/16 is not present, the sum is less than 1; 16 is the ninth composite number.

MATHEMATICA

NextComposite[n_] := Block[{k = n + 1}, While[PrimeQ[k], k++ ]; k]; s=0; k = 4; Do[While[s = s + 1/k; s < n, k = NextComposite[k]]; Print[k - PrimePi[k] - 1]; k = NextComposite[k], {n, 1, 20}]

CROSSREFS

Cf. A002387, A016088, A046024, A002808, A004080.

Sequence in context: A036599 A229404 A059825 * A084903 A034558 A144109

Adjacent sequences:  A074628 A074629 A074630 * A074632 A074633 A074634

KEYWORD

nonn,nice

AUTHOR

Labos Elemer, Aug 27 2002

EXTENSIONS

Edited by Robert G. Wilson v, Aug 28 2002

More terms from Robert Gerbicz, Aug 30 2002

2 more terms from Robert G. Wilson v, Sep 03 2002

STATUS

approved

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Last modified November 17 13:33 EST 2019. Contains 329230 sequences. (Running on oeis4.)