cp's OEIS Frontend

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.

A127702 Least value of x*y giving Max ( sigma(x*y) : 1<=x<=n, 1<=y<=n ).

This page as a plain text file.
%I A127702 #12 Mar 31 2012 10:31:16
%S A127702 1,4,9,16,20,36,42,64,72,90,90,144,144,168,210,240,240,324,324,360,
%T A127702 420,420,420,576,600,600,600,756,756,840,840,960,960,960,960,1260,
%U A127702 1260,1260,1260,1560,1560,1680,1680,1680,1980,1980,1980,2160,2160,2400,2400
%N A127702 Least value of x*y giving Max ( sigma(x*y) : 1<=x<=n, 1<=y<=n ).
%C A127702 Value is unique by this definition up to a(103) = 9900.  To go beyond this number, we could define the sequence in terms of "smallest value of x*y" or "largest value of x*y". We choose smallest here.
%e A127702 a(5) = 4 * 5 = 20; sigma(20) = 42
%Y A127702 Cf. A074963, A074964.
%K A127702 nonn
%O A127702 1,2
%A A127702 _Stewart Gordon_, Sep 26 2011