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A118224 Smallest number having at least 2*n divisors. 3
2, 6, 12, 24, 48, 60, 120, 120, 180, 240, 360, 360, 720, 720, 720, 840, 1260, 1260, 1680, 1680, 2520, 2520, 2520, 2520, 5040, 5040, 5040, 5040, 5040, 5040, 7560, 7560, 10080, 10080, 10080, 10080, 15120, 15120, 15120, 15120, 20160, 20160, 25200, 25200, 25200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Michael S. Branicky, Table of n, a(n) for n = 1..1000

FORMULA

A000005(a(n)) >= 2*n;

a(n) = A061799(2*n).

a(n) <= A003680(n). - Michael S. Branicky, Feb 06 2021

PROG

(Python)

from sympy import divisors

def a(n):

  m = 4*n - 2

  while len(divisors(m)) < 2*n: m += 1

  return m

print([a(n) for n in range(1, 46)]) # Michael S. Branicky, Feb 06 2021

CROSSREFS

Cf. A086921, A003680 (exactly 2n).

Sequence in context: A307211 A294545 A305104 * A227068 A003680 A337257

Adjacent sequences:  A118221 A118222 A118223 * A118225 A118226 A118227

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Apr 16 2006

STATUS

approved

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Last modified September 18 09:05 EDT 2021. Contains 347518 sequences. (Running on oeis4.)