login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A137487 Numbers with 24 divisors. 3
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 (list; graph; refs; listen; history; text; internal format)
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

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

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

CROSSREFS

Cf. A030513-A030516, A030626, A030627, A030634-A030638, A005179, A003680, A096932, A061286, A061283.

Sequence in context: A185641 A031966 A170830 * A069478 A060665 A072414

Adjacent sequences:  A137484 A137485 A137486 * A137488 A137489 A137490

KEYWORD

nonn

AUTHOR

R. J. Mathar, Apr 22 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 4 17:23 EST 2016. Contains 278754 sequences.