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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A175749 Numbers with 40 divisors. 3
1680, 2160, 2640, 3024, 3120, 3240, 3696, 4080, 4368, 4536, 4560, 4752, 5520, 5616, 5670, 5712, 6000, 6160, 6384, 6864, 6960, 7128, 7280, 7344, 7440, 7680, 7728, 8208, 8424, 8880, 8910, 8976, 9520, 9744, 9840, 9936, 10032, 10320, 10368, 10416, 10530, 10608 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers of the forms p^39, p^19*q^1, p^9*q^3, p^7*q^4, p^9*q^1*r^1, p^4*q^3*r^1, and p^4*q^1*r^1*s^1, where p, q, r, and s are distinct primes.

LINKS

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

OEIS Wiki, Index entries for number of divisors

FORMULA

A000005(a(n))=40.

MATHEMATICA

Select[Range[20000], DivisorSigma[0, #]==40&] (* Vladimir Joseph Stephan Orlovsky, May 06 2011 *)

PROG

(PARI) is(n)=numdiv(n)==40 \\ Charles R Greathouse IV, Jun 19 2016

CROSSREFS

Cf. A175747, A175748.

Sequence in context: A093787 A258920 A268288 * A231548 A179693 A290704

Adjacent sequences:  A175746 A175747 A175748 * A175750 A175751 A175752

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Aug 27 2010

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 18 02:23 EDT 2019. Contains 328135 sequences. (Running on oeis4.)