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A098893 Sum of number of prime-factors of all prefixes in decimal representation of n. 0
0, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 3, 1, 2, 2, 4, 1, 3, 1, 4, 3, 3, 2, 5, 3, 3, 4, 4, 2, 4, 2, 6, 3, 3, 3, 5, 2, 3, 3, 6, 3, 5, 3, 5, 5, 4, 3, 7, 4, 4, 3, 4, 2, 5, 3, 5, 3, 3, 2, 6, 3, 4, 5, 8, 4, 5, 3, 5, 4, 4, 2, 6, 2, 3, 4, 4, 3, 4, 2, 8, 7, 5, 4, 7, 5, 5, 5, 7, 4, 6, 4, 5, 4, 4, 4, 8, 3, 5, 5, 6, 3, 5, 3, 6, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(n) = if n<10 then Omega(n) else Omega(n) + a(floor(n/10)), where Omega=A001222.

LINKS

Table of n, a(n) for n=1..105.

EXAMPLE

a(256)=Omega(256)+a(25)=8+Omega(25)+a(2)=8+2+Omega(2)=10+1=11.

CROSSREFS

Sequence in context: A319269 A296132 A253557 * A302037 A069248 A008481

Adjacent sequences:  A098890 A098891 A098892 * A098894 A098895 A098896

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Nov 04 2004

STATUS

approved

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Last modified September 22 22:42 EDT 2018. Contains 315270 sequences. (Running on oeis4.)