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

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A144672 Numbers x,y,z such that UnitarySigma(x) = UnitarySigma(y) = UnitarySigma(z) = 3*(x*y*z)^(1/2)/(- x^(1/2) + 8*y^(1/2) - 5*z^(1/2)), z<=y<=x; sequence gives x. 4
2, 20, 24, 360, 816, 1056, 12240, 15840, 29120, 181632, 337977, 2724480, 93358848, 1400382720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(11) is the smallest term for x!=y, y!=z, x!=z

If x=y=z then we get multiply unitary perfect numbers such that UnitarySigma(x)=3x/2.

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

Factorization of a(11) : 17*3^2*47^2

CROSSREFS

Cf. A144673, A144674 (these entries all differ at a(11)).

Sequence in context: A196748 A144674 A144673 * A145681 A108061 A154546

Adjacent sequences:  A144669 A144670 A144671 * A144673 A144674 A144675

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto, Feb 02 2009

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 May 27 07:51 EDT 2017. Contains 287202 sequences.