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A327328 a(n) is the smallest positive integer divisible by exactly n nonpowers of 2. 1
1, 3, 6, 12, 18, 45, 30, 105, 72, 60, 90, 315, 120, 3645, 210, 180, 450, 1575, 480, 2835, 360, 420, 630, 3465, 900, 720, 7290, 1620, 840, 14175, 1440, 10395, 1800, 1260, 3150, 1680, 3240, 1937102445, 5670, 14580, 3600, 127575, 3360, 2066715, 2520, 3780, 6930 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Terms are of the form A233819(m) * 2^k for some m > 0, k >= 0. - David A. Corneth, Nov 25 2019

LINKS

David A. Corneth, Table of n, a(n) for n = 0..1000

PROG

(PARI) ispp(x) = my(p); (x == 1) || (isprimepower(x, &p) && (p==2));

nbdiv(k) = #select(x->(!ispp(x)), divisors(k));

a(n) = my(k=1); while (nbdiv(k) != n, k++); k; \\ Michel Marcus, Nov 25 2019

(PARI) a(n) = for(i = 1, oo, if(numdiv(i) - valuation(i, 2) - 1 == n, return(i))) \\ David A. Corneth, Nov 25 2019

CROSSREFS

Cf. A057716, A233819, A326987, A326989.

Sequence in context: A061776 A341316 A298029 * A074899 A318872 A267591

Adjacent sequences:  A327325 A327326 A327327 * A327329 A327330 A327331

KEYWORD

nonn

AUTHOR

Omar E. Pol, Sep 20 2019

EXTENSIONS

a(13)-a(36), a(38)-a(46) from Jon E. Schoenfield, Nov 22 2019

a(37) from Jon E. Schoenfield and David A. Corneth, Nov 25 2019

STATUS

approved

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Last modified June 25 04:52 EDT 2021. Contains 345452 sequences. (Running on oeis4.)