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 A169611 Number of prime divisors of n that are not greater than 3, counted with multiplicity. 10
 0, 1, 1, 2, 0, 2, 0, 3, 2, 1, 0, 3, 0, 1, 1, 4, 0, 3, 0, 2, 1, 1, 0, 4, 0, 1, 3, 2, 0, 2, 0, 5, 1, 1, 0, 4, 0, 1, 1, 3, 0, 2, 0, 2, 2, 1, 0, 5, 0, 1, 1, 2, 0, 4, 0, 3, 1, 1, 0, 3, 0, 1, 2, 6, 0, 2, 0, 2, 1, 1, 0, 5, 0, 1, 1, 2, 0, 2, 0, 4, 4, 1, 0, 3, 0, 1, 1, 3, 0, 3, 0, 2, 1, 1, 0, 6, 0, 1, 2, 2, 0, 2, 0, 3, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A001222(n) - A106799(n). a(n) = A007814(n) + A007949(n). - R. J. Mathar, Dec 04 2009 a(n) = A001222(A065331(n)). - Reinhard Zumkeller, Nov 19 2015 Asymptotic mean: lim_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 3/2. - Amiram Eldar, Jan 16 2022 MAPLE A169611 := proc(n) local f; a := 0 ; for f in ifactors(n)[2] do if op(1, f) <= 3 then a := a+op(2, f) ; end if; end do: return a; end proc: seq(A169611(n), n=1..100) ; # R. J. Mathar, Dec 04 2009 MATHEMATICA f[n_] := Plus @@ Last /@ Select[ FactorInteger@ n, 1 < #[[1]] < 4 &]; Array[f, 105] (* Robert G. Wilson v, Dec 19 2009 *) PROG (PARI) A169611(n)=valuation(n, 2)+valuation(n, 3)  \\ M. F. Hasler, Aug 24 2012 (Haskell) a169611 = a001222 . a065331  -- Reinhard Zumkeller, Nov 19 2015 CROSSREFS Cf. A001222, A106799. Cf. A007814, A007949, A065331. Sequence in context: A273846 A090290 A153585 * A242460 A144494 A136166 Adjacent sequences:  A169608 A169609 A169610 * A169612 A169613 A169614 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Dec 03 2009 EXTENSIONS Definition corrected by M. F. Hasler, Aug 24 2012 STATUS approved

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Last modified August 18 12:46 EDT 2022. Contains 356212 sequences. (Running on oeis4.)