|
| |
|
|
A139719
|
|
A number n is included if k + n/k divides n for at least one divisor k of n.
|
|
2
| |
|
|
4, 16, 18, 36, 48, 64, 72, 100, 144, 150, 162, 180, 192, 196, 256, 288, 294, 324, 400, 432, 448, 450, 484, 490, 576, 588, 600, 648, 676, 720, 768, 784, 882, 900, 960, 1024, 1134, 1152, 1156, 1176, 1200, 1210, 1296, 1350, 1444, 1458, 1584, 1600, 1620, 1728
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| All terms are even. All even perfect squares are included. If n is included, then 4n is also included.
Also the set of all numbers n of the form n = r*s*(r+s)^2*t^2 with positive integers r,s,t; if one additionally requires (r,s) = 1 and r <= s, then there is exactly one such representation for each n. [From Hagen von Eitzen (math(AT)von-eitzen.de), Jul 22 2009]
|
|
|
EXAMPLE
| 72 is included because 6 is a divisor of 72 and (6 + 72/6) = 18 divides 72.
|
|
|
CROSSREFS
| Cf. A139718.
Sequence in context: A178364 A034121 A166620 * A117102 A077476 A175527
Adjacent sequences: A139716 A139717 A139718 * A139720 A139721 A139722
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Leroy Quet May 01 2008
|
|
|
EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jul 01 2009
|
| |
|
|
