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A276651
a(n) = numerator of Sum_{p|n} 0.d where p runs through the prime divisors of n.
6
1, 3, 1, 1, 1, 7, 1, 3, 7, 11, 1, 13, 9, 4, 1, 17, 1, 19, 7, 1, 31, 23, 1, 1, 33, 3, 9, 29, 1, 31, 1, 41, 37, 6, 1, 37, 39, 43, 7, 41, 6, 43, 31, 4, 43, 47, 1, 7, 7, 47, 33, 53, 1, 61, 9, 49, 49, 59, 1, 61, 51, 1, 1, 63, 61, 67, 37, 53, 7, 71, 1, 73, 57, 4, 39
OFFSET
2,2
COMMENTS
Here 0.d means the decimal fraction obtained by writing d after the decimal point, e.g., 0.11 = 11/100.
The first few values of Sum_{p|n} 0.d are: 1/5, 3/10, 1/5, 1/2, 1/2, 7/10, 1/5, 3/10, 7/10, ...
See A276655 - numbers n such that Sum_{p|n} 0.d is an integer.
LINKS
FORMULA
a(n) = (Sum_{p|n} 0.d) * A276652(n) where p = prime divisors of n.
EXAMPLE
For n=12; Sum_{p|12} 0.d = 0.2 + 0.3 = 0.5 = 5/10 = 1/2; a(12) = 1.
MATHEMATICA
Numerator[Table[f = FactorInteger[i][[All, 1]];
Total[f*10^-IntegerLength[f]], {i, 2, 76}]] (* Robert Price, Sep 20 2019 *)
PROG
(Magma) [Numerator(&+[d/(10^(#Intseq(d))): d in PrimeDivisors(n)]): n in [2..1000]]
CROSSREFS
KEYWORD
nonn,base,frac
AUTHOR
Jaroslav Krizek, Sep 10 2016
STATUS
approved