A095407 Total number of decimal digits of all distinct prime factors of n.

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

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

Cf. A055642, A001221.

Sequence in context: A104360 A318998 A079951 * A038605 A113121 A109036

Adjacent sequences: A095404 A095405 A095406 * A095408 A095409 A095410

Keyword

base,nonn

Author

Labos Elemer, Jun 21 2004

Status

approved