

A125491


Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives y numbers.


5



2016, 9504, 22200, 31284, 41412, 40068, 40608, 43890, 54990, 52290, 53676, 69030, 69420, 77688, 83720, 84252, 82236, 80892, 87750, 93870, 96048, 97416, 107040, 129108, 129504, 137610, 127908, 156450, 144936, 152520
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Giovanni Resta computed these terms.
As stated, we first order by common sigma value. When the common value of sigma is the same for several triples, these are then sorted (ascending) by the smallest member. When the smallest members also agree, we go on to the second smallest members, and so on, lexicographically.  John Cerkan, Jun 18 2016


LINKS

John Cerkan, Table of n, a(n) for n = 1..10000 [Terms 1 through 1000 were computed by Donovan Johnson]


EXAMPLE

2016 is in the sequence since sigma(1980) = sigma(2016) = sigma(2556) = 6552 = 1980 + 2016 + 2556.  Michael B. Porter, Jun 29 2016


CROSSREFS

Cf. A125490, A125492, A137231 (x+y+z).
Cf. A000203 (sigma function).
Sequence in context: A076666 A189188 A076582 * A166818 A166800 A223216
Adjacent sequences: A125488 A125489 A125490 * A125492 A125493 A125494


KEYWORD

nonn


AUTHOR

Yasutoshi Kohmoto, Dec 11 2006


EXTENSIONS

Definition corrected by N. J. A. Sloane, Nov 27 2008
a(13)a(30) from Donovan Johnson, Apr 14 2010


STATUS

approved



