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A095407 Total number of decimal digits of all distinct prime factors of n. 9
0, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 3, 2, 2, 1, 3, 1, 2, 2, 3, 2, 1, 3, 3, 2, 2, 2, 3, 3, 2, 2, 3, 2, 3, 2, 3, 2, 2, 1, 2, 3, 3, 2, 2, 3, 2, 3, 3, 2, 3, 2, 3, 2, 1, 3, 4, 2, 3, 3, 3, 2, 2, 2, 3, 2, 3, 3, 4, 2, 2, 1, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 2, 2, 2, 3, 2, 3, 4, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,6
COMMENTS
a(n) <= A055642(n) + A001221(n) - 1 since the product of a k digit number and an m digit number has at least k+m-1 digits. - Chai Wah Wu, Nov 03 2019
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
n=22: prime set={2,11}, a[22]=1+2=3.
MATHEMATICA
Prepend[(Total [ Length[IntegerDigits[#]] & /@ ( #[[1]] & /@ FactorInteger[#])] & /@ Range[2, 105]), 0] (* Zak Seidov, Aug 26 2016 *)
PROG
(PARI) a(n)=vecsum(apply(p->#Str(p), factor(n)[, 1])) \\ Charles R Greathouse IV, Aug 26 2016
CROSSREFS
Sequence in context: A104360 A318998 A079951 * A038605 A113121 A109036
KEYWORD
base,nonn
AUTHOR
Labos Elemer, Jun 21 2004
STATUS
approved

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Last modified April 19 18:05 EDT 2024. Contains 371798 sequences. (Running on oeis4.)