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.

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

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: A323749 A323469 A343178 * 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