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A137487
Numbers with 24 divisors.
4
360, 420, 480, 504, 540, 600, 630, 660, 672, 756, 780, 792, 864, 924, 936, 990, 1020, 1050, 1056, 1092, 1120, 1140, 1152, 1170, 1176, 1188, 1224, 1248, 1350, 1368, 1380, 1386, 1400, 1404, 1428, 1470, 1500, 1530, 1540, 1596, 1632, 1638, 1650, 1656, 1710
OFFSET
1,1
COMMENTS
Maple implementation: see A030513.
Numbers of the form p^23, p^2*q^7, p*q^2*r^3 (like 360, 504), p*q*r^5 (like 480, 672), p*q*r*s^2 (like 420, 660), p^3*q^5 (like 864) or p*q^11, where p, q, r and s are distinct primes. - R. J. Mathar, Mar 01 2010
FORMULA
A000005(a(n))=24.
MATHEMATICA
Select[Range[3000], DivisorSigma[0, #]==24&] (* Vladimir Joseph Stephan Orlovsky, May 05 2011 *)
PROG
(PARI) is(n)=numdiv(n)==24 \\ Charles R Greathouse IV, Jun 19 2016
KEYWORD
nonn
AUTHOR
R. J. Mathar, Apr 22 2008
STATUS
approved