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A276513 a(n) = the smallest number k>1 such that Sum_{p|k} 0.p = n where p runs through the prime divisors of k. 6
21, 16102, 281785, 275867515 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

a(n) = the smallest number k>1 such that A276651(k) / A276652(k) = n.

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, ...

Conjecture: a(4) = 730610790; Sum_{p|730610790} 0.p = 0.2 + 0.3 + 0.5 + 0.7 + 0.13 + 0.31 + 0.89 + 0.97 = 4.

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

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

Number 16102 is the smallest number k with Sum_{p|k} 0.p = 2; set of prime divisors of 16102: {2, 83, 97}; Sum_{p|16102} 0.p = 0.2 + 0.83 + 0.97 = 2.

PROG

(MAGMA) A276513:=func<n|exists(r){k:k in[2..10^6] | (&+[d / (10^(#Intseq(d))): d in PrimeDivisors(k)]) eq n}select r else 0>; [A276513(n): n in[1..3]]

CROSSREFS

Cf. A005117, A276651, A276652, A276653, A276654, A276655.

Sequence in context: A180769 A220643 A185557 * A167063 A115485 A172724

Adjacent sequences:  A276510 A276511 A276512 * A276514 A276515 A276516

KEYWORD

nonn,base,more

AUTHOR

Jaroslav Krizek, Sep 14 2016

EXTENSIONS

a(4) from Chai Wah Wu, Sep 16 2016

STATUS

approved

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Last modified July 21 21:14 EDT 2019. Contains 325199 sequences. (Running on oeis4.)