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 A079065 In prime factorization of n replace odd primes with 3. 2
 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)<

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Last modified January 26 13:42 EST 2022. Contains 350598 sequences. (Running on oeis4.)