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A030636 Numbers with 18 divisors. 10
180, 252, 288, 300, 396, 450, 468, 588, 612, 684, 700, 768, 800, 828, 882, 972, 980, 1044, 1100, 1116, 1280, 1300, 1332, 1452, 1476, 1548, 1568, 1575, 1692, 1700, 1792, 1900, 1908, 2028, 2124, 2156, 2178, 2196, 2205, 2300, 2412, 2420, 2450 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers of the form p^17, p*q^8, p*q^2*r^2 or p^2*q^5, where p, q and r are distinct primes. - R. J. Mathar, Mar 01 2010

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[2500], DivisorSigma[0, #]==18&]  (* Harvey P. Dale, Feb 01 2011 *)

PROG

(PARI) is(n)=numdiv(n)==18 \\ Charles R Greathouse IV, Jun 19 2016

CROSSREFS

Cf. A030635 (17 divs), A030637 (19 divs).

Sequence in context: A291457 A289056 A309380 * A179643 A160134 A135193

Adjacent sequences:  A030633 A030634 A030635 * A030637 A030638 A030639

KEYWORD

nonn

AUTHOR

Jeff Burch

EXTENSIONS

882 inserted by N. J. A. Sloane, Mar 26 2007

STATUS

approved

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Last modified October 21 03:24 EDT 2019. Contains 328291 sequences. (Running on oeis4.)