|
|
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
|
|
|
|
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, ...
|
|
LINKS
|
|
|
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.
|
|
MATHEMATICA
|
Table[k = 2; While[f = FactorInteger[k][[All, 1]];
Floor[Total[f*10^-IntegerLength[f]]] != n, k++];
|
|
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
|
|
|
KEYWORD
|
nonn,base,more
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|