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A285038 a(n) = least k such that k*n belongs to A120383. 1
1, 1, 2, 1, 6, 1, 4, 1, 2, 3, 30, 1, 6, 2, 2, 1, 28, 1, 8, 3, 4, 15, 18, 1, 6, 3, 2, 1, 30, 1, 330, 1, 10, 14, 12, 1, 12, 4, 2, 3, 78, 2, 28, 15, 2, 9, 30, 1, 4, 3, 28, 3, 16, 1, 6, 1, 8, 15, 476, 1, 18, 165, 4, 1, 6, 5, 152, 7, 6, 6, 60, 1, 84, 6, 2, 2, 60, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(2*k+1) is even for any k > 0.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10000

EXAMPLE

5 = prime(3); as 5 is coprime to 3, a(5) must be a multiple of 3; 5*3 = prime(3)*prime(2) does not belong to A120383 as it is not divisible by 2; so a(5) must also be divisible by 2; 5*3*2 belongs to A120383, hence a(5) = 3*2 = 6.

7 = prime(4); as 7 is coprime to 4, a(7) must be a multiple of 4; 7*4 belongs to A120383, hence a(7)=4.

PROG

(PARI) complete(n) = my (c=n); my (f=factor(n)); for (i=1, #f~, c = lcm(c, primepi(f[i, 1]))); return (c)

a(n) = my (m=n); while (1, my (mm=complete(m)); if (m==mm, return (m/n), m=mm))

CROSSREFS

Cf. A120383.

Sequence in context: A304527 A321725 A154744 * A243145 A306695 A242926

Adjacent sequences:  A285035 A285036 A285037 * A285039 A285040 A285041

KEYWORD

nonn

AUTHOR

Rémy Sigrist, Apr 08 2017

STATUS

approved

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Last modified January 19 20:41 EST 2020. Contains 331066 sequences. (Running on oeis4.)