login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A091014 Smallest number having exactly n divisors d such that for some x also d-x and d+x are divisors. 1
1, 6, 18, 12, 30, 24, 36, 48, 132, 84, 72, 60, 312, 264, 816, 144, 270, 168, 252, 300, 288, 120, 810, 432, 1224, 180, 1188, 1140, 792, 630, 1152, 240, 2112, 672, 4104, 504, 420, 600, 3672, 540, 1872, 480, 2592, 1584, 900, 5100, 360, 2760, 2040, 1890 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A091009(a(n))=n and A091009(m)<>n for m<=a(n).

LINKS

Table of n, a(n) for n=0..49.

EXAMPLE

a(9)=84: the exactly 9 triples of divisors of 84 with the defining property: (1,2,3), (2,3,4), (2,4,6), (1,4,7), (2,7,12), (3,12,21), (7,14,21), (14,21,28) and (14,28,42).

CROSSREFS

Sequence in context: A129870 A331056 A274877 * A097370 A252897 A174904

Adjacent sequences:  A091011 A091012 A091013 * A091015 A091016 A091017

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Dec 13 2003

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 May 14 16:48 EDT 2021. Contains 343898 sequences. (Running on oeis4.)