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A079065 In prime factorization of n replace odd primes with 3. 1
1, 2, 3, 4, 3, 6, 3, 8, 9, 6, 3, 12, 3, 6, 9, 16, 3, 18, 3, 12, 9, 6, 3, 24, 9, 6, 27, 12, 3, 18, 3, 32, 9, 6, 9, 36, 3, 6, 9, 24, 3, 18, 3, 12, 27, 6, 3, 48, 9, 18, 9, 12, 3, 54, 9, 24, 9, 6, 3, 36, 3, 6, 27, 64, 9, 18, 3, 12, 9, 18, 3, 72, 3, 6, 27, 12, 9, 18, 3, 48, 81, 6, 3, 36, 9, 6, 9, 24, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) <= n; a(n)=n iff n is 3-smooth (A003586);

A065333(a(n)) = 1;

a(a(n)) = a(n);

A001221(a(n)) <= A001221(n);

A001222(a(n)) = A001222(n);

A006519(a(n)) = A006519(n).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

FORMULA

Fully multiplicative with a(2) = 2, a(p) = 3 for odd primes p.

PROG

(PARI) A079065(n) =  { my(f=factor(n)); for(i=1, #f~, if(f[i, 1]%2, f[i, 1] = 3)); factorback(f); }; \\ Antti Karttunen, Sep 27 2018

(PARI) a(n) = my(e2 = valuation(n, 2)); 3^(bigomega(n) - e2)<<e2 \\ David A. Corneth, Sep 27 2018

CROSSREFS

Sequence in context: A086369 A092089 A117659 * A097272 A126630 A167234

Adjacent sequences:  A079062 A079063 A079064 * A079066 A079067 A079068

KEYWORD

nonn,mult

AUTHOR

Reinhard Zumkeller, Feb 02 2003

STATUS

approved

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Last modified May 26 02:56 EDT 2020. Contains 334613 sequences. (Running on oeis4.)