OFFSET
1,1
COMMENTS
Numbers belonging to aliquot cycles of length greater than 2.
There is no proof that 564 (for example) is missing from this sequence (cf. A122726). - N. J. A. Sloane, Sep 17 2021
The lengths of the corresponding aliquot cycles are given by A052470. - Michel Marcus, Nov 15 2013
REFERENCES
R. K. Guy, Unsolved Problems Number Theory, B7.
P. Poulet, Parfaits, amiables et extensions, Editions Stevens, Bruxelles, 1918.
D. Wells, The Penguin Dictionary of Curious and Interesting Numbers, pp. 174 Penguin Books 1987.
LINKS
Jeppe Stig Nielsen, Table of n, a(n) for n = 1..53
V. E. Hoggart, Jr., Letters to N. J. A. Sloane, 1974-1975
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 112
D. Moews, Perfect, amicable and sociable numbers
D. Moews, A list of currently known aliquot cycles of length greater than 2 [This list is not known to be complete.]
J. O. M. Pedersen, Tables of Aliquot Cycles [Broken link]
J. O. M. Pedersen, Tables of Aliquot Cycles [Via Internet Archive Wayback-Machine]
J. O. M. Pedersen, Tables of Aliquot Cycles [Cached copy, pdf file only]
Eric Weisstein's World of Mathematics, Sociable Numbers.
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Incorrect g.f. deleted by N. J. A. Sloane, Sep 20 2008
Added "conjectured" to definition. - N. J. A. Sloane, Sep 17 2021
STATUS
approved