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A276654 a(n) = the smallest number k>1 such that floor(Sum_{p|k} 0.p) = n where p runs through the prime divisors of k. 6
2, 21, 2905, 281785, 47740490 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Here 0.p means the decimal fraction obtained by writing p after the decimal point, e.g. 0.11 = 11/100.

The first few values of Sum_{p|n} 0.p are: 1/5, 3/10, 1/5, 1/2, 1/2, 7/10, 1/5, 3/10, 7/10, ...

Subsequence of A005117. - Chai Wah Wu, Sep 15 2016

LINKS

Table of n, a(n) for n=0..4.

EXAMPLE

Number 2905 is the smallest number k with floor(Sum_{p|k} 0.p) = 2; set of prime divisors of 2905: {5, 7, 83}; floor(Sum_{p|2905} 0.p) = 0.5 + 0.7 + 0.83 = floor(2.03) = 2.

PROG

(MAGMA) A276654:=func<n|exists(r){k:k in[2..1000000] | Floor(&+[d / (10^(#Intseq(d))): d in PrimeDivisors(k)]) eq n}select r else 0>; [A276654(n): n in[0..3]]

CROSSREFS

Cf. A005117, A276513, A276651, A276652, A276653, A276655.

Sequence in context: A050204 A022470 A080815 * A114846 A195165 A201973

Adjacent sequences:  A276651 A276652 A276653 * A276655 A276656 A276657

KEYWORD

nonn,base,more

AUTHOR

Jaroslav Krizek, Sep 11 2016

EXTENSIONS

a(4) from Michel Marcus, Sep 11 2016

STATUS

approved

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Last modified June 15 20:50 EDT 2019. Contains 324145 sequences. (Running on oeis4.)