This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A125490 #25 Jul 02 2016 01:59:03 %S A125490 1980,9180,21168,23940,37380,38940,38940,39480,46368,47124,53088, %T A125490 57420,66720,67860,69720,73320,75180,77490,72072,86040,93456,96660, %U A125490 92820,100980,100980,112140,118944,121800,139080,141372 %N A125490 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 x numbers. %C A125490 G. Resta computed these terms. %C A125490 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 %H A125490 John Cerkan, <a href="/A125490/b125490.txt">Table of n, a(n) for n = 1..10000</a> [Terms 1 through 1000 were computed by Donovan Johnson] %e A125490 1980 is in the sequence since sigma(1980) = sigma(2016) = sigma(2556) = 6552 = 1980 + 2016 + 2556. - _Michael B. Porter_, Jun 29 2016 %Y A125490 Cf. A125491, A125492, A137231 (x+y+z). %Y A125490 Cf. A036471 - A036474 and A116148 (amicable quadruples). %Y A125490 Cf. A233553 for amicable 5-tuples. %Y A125490 Cf. A000203 (sigma function). %K A125490 nonn %O A125490 1,1 %A A125490 _Yasutoshi Kohmoto_, Dec 11 2006 %E A125490 Definition corrected by _N. J. A. Sloane_, Nov 27 2008 %E A125490 a(13)-a(30) from _Donovan Johnson_, Apr 14 2010