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



Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A003416 Sociable numbers: smallest member of each cycle. 9


%S 12496,14316,1264460,2115324,2784580,4938136,7169104,18048976,

%T 18656380,28158165,46722700,81128632,174277820,209524210,330003580,

%U 498215416,805984760,1095447416,1236402232,1276254780,1799281330

%N Sociable numbers: smallest member of each cycle.

%C Numbers belonging to aliquot cycles of length greater than 2.

%C The lengths of the corresponding aliquot cycles are given by A052470. - _Michel Marcus_, Nov 15 2013

%D R. K. Guy, Unsolved Problems Number Theory, B7.

%D P. Poulet, Parfaits, amiables et extensions, Editions Stevens, Bruxelles, 1918.

%D D. Wells, The Penguin Dictionary of Curious and Interesting Numbers, pp. 174 Penguin Books 1987.

%H Jeppe Stig Nielsen, <a href="/A003416/b003416.txt">Table of n, a(n) for n = 1..53</a>

%H V. E. Hoggart, Jr., <a href="/A003416/a003416.pdf">Letters to N. J. A. Sloane, 1974-1975</a>

%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=112">Encyclopedia of Combinatorial Structures 112</a>

%H D. Moews, <a href="http://djm.cc/amicable.html">Perfect, amicable and sociable numbers</a>

%H D. Moews, <a href="http://djm.cc/sociable.txt">Sociable numbers</a>

%H J. O. M. Pedersen, <a href="http://amicable.homepage.dk/tables.htm">Tables of Aliquot Cycles</a> [Broken link]

%H J. O. M. Pedersen, <a href="http://web.archive.org/web/20140502102524/http://amicable.homepage.dk/tables.htm">Tables of Aliquot Cycles</a> [Via Internet Archive Wayback-Machine]

%H J. O. M. Pedersen, <a href="/A063990/a063990.pdf">Tables of Aliquot Cycles</a> [Cached copy, pdf file only]

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SociableNumbers.html">Sociable Numbers.</a>

%Y Cf. A072890, A072891.

%K nonn,nice

%O 1,1

%A _N. J. A. Sloane_

%E Incorrect g.f. deleted by _N. J. A. Sloane_, Sep 20 2008

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 January 19 00:40 EST 2020. Contains 331030 sequences. (Running on oeis4.)