

A076649


Number of digits required to write the prime factors of n.


6



0, 1, 1, 2, 1, 2, 1, 3, 2, 2, 2, 3, 2, 2, 2, 4, 2, 3, 2, 3, 2, 3, 2, 4, 2, 3, 3, 3, 2, 3, 2, 5, 3, 3, 2, 4, 2, 3, 3, 4, 2, 3, 2, 4, 3, 3, 2, 5, 2, 3, 3, 4, 2, 4, 3, 4, 3, 3, 2, 4, 2, 3, 3, 6, 3, 4, 2, 4, 3, 3, 2, 5, 2, 3, 3, 4, 3, 4, 2, 5, 4, 3, 2, 4, 3, 3, 3, 5, 2, 4, 3, 4, 3, 3, 3, 6, 2, 3, 4, 4, 3, 4, 3, 5, 3, 3
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OFFSET

1,4


LINKS



FORMULA

a(n) is completely additive: a(m*n) = a(m)+a(n) for all integers m, n >= 1, with a(1)=0 and a(p^e) = e*floor(log_10(10*p)), p prime.  Diego Torres (torresvillarroel(AT)hotmail.com), Oct 26 2002
Totally additive with a(p) = A055642(p).


EXAMPLE

12 = 2*2*3 so a(12)=3.


MATHEMATICA

Join[{0}, Table[Total[IntegerLength[#]&/@(Flatten[Table[#[[1]], #[[2]]]&/@ FactorInteger[n]])], {n, 2, 120}]] (* Harvey P. Dale, Mar 10 2018 *)


PROG



CROSSREFS



KEYWORD

base,nonn


AUTHOR



EXTENSIONS



STATUS

approved



