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A106799 Number of prime factors of n apart from 2 or 3, counted with multiplicity. 3
0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 2, 1, 0, 1, 1, 1, 1, 0, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 1, 1, 1, 1, 2, 1, 0, 1, 1, 2, 1, 2, 1, 1, 1, 0, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 0, 1, 2, 1, 2, 1, 1, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,25

COMMENTS

Self-similar in every second and in every third term, i.e. a(n)=a(2n)=a(3n). Logarithmic since a(b*c)=a(b)+a(c). Coincidentally, a(n)=A101040(n+78) for 1<n<20.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

a(n) =A001222(n)-A007814(n)-A007949(n) =A087436(n)-A007949(n).

a(n) = A001222(A065330(n)). - Reinhard Zumkeller, May 19 2005

EXAMPLE

a(24)=0 since 24=(2*2*2*3); a(25)=2 since 25=5*5; a(26)=1 since 26=(2)*13.

PROG

(Haskell)

a106799 = a001222 . a065330  -- Reinhard Zumkeller, Nov 19 2015

CROSSREFS

Cf. A001222, A007814, A007949, A027746, A065330, A087436, A101040, A169611.

Sequence in context: A037853 A255237 A291954 * A212210 A127499 A198068

Adjacent sequences:  A106796 A106797 A106798 * A106800 A106801 A106802

KEYWORD

nonn

AUTHOR

Henry Bottomley, May 17 2005

STATUS

approved

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Last modified August 17 17:25 EDT 2019. Contains 326059 sequences. (Running on oeis4.)