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A079707 In prime factorization of n replace odd primes with their prime predecessor. 0
1, 2, 2, 4, 3, 4, 5, 8, 4, 6, 7, 8, 11, 10, 6, 16, 13, 8, 17, 12, 10, 14, 19, 16, 9, 22, 8, 20, 23, 12, 29, 32, 14, 26, 15, 16, 31, 34, 22, 24, 37, 20, 41, 28, 12, 38, 43, 32, 25, 18, 26, 44, 47, 16, 21, 40, 34, 46, 53, 24, 59, 58, 20, 64, 33, 28, 61, 52, 38, 30, 67, 32, 71, 62, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)<=n; a(n)<n iff n>1 is odd; a(n)=n iff n=2^k;

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

for 3-smooth numbers: a(2^i * 3^j) = 2^(i+j);

result after A061395(n)-1 iterations = A061142(n).

LINKS

Table of n, a(n) for n=1..75.

FORMULA

Multiplicative with 2->2 and prime(k)->prime(k-1), k>1.

CROSSREFS

Cf. A005408, A000079, A003586, A003961.

Sequence in context: A171580 A246796 A177235 * A233511 A205793 A178431

Adjacent sequences:  A079704 A079705 A079706 * A079708 A079709 A079710

KEYWORD

nonn,mult

AUTHOR

Reinhard Zumkeller, Jan 31 2003

STATUS

approved

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Last modified February 18 04:48 EST 2020. Contains 332011 sequences. (Running on oeis4.)