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 A235230 #17 Sep 15 2024 13:05:27
%S A235230 1,6,15,364,585,5052,9573,191714,13682428
%N A235230 Integer radii of circles tiled by square tiles such that the ratio of uncut tiles to cut tiles is an integer and four square tiles meet at the center of the circle.
%C A235230 It is my conjecture that there are an infinite number of solutions and that they occur by chance, accounting for the widening gaps between valid answers as the number of digits for the sums of tiles increases.
%C A235230 The inspiration for this problem came from Enigma #1686 of the New Scientist Magazine.
%C A235230 The values involved are the following {a(n), #uncut, cut, ratio} : {1, 0, 4, 0}, {6, 88, 44, 2}, {15, 648, 108, 6}, {364, 414700, 2900, 143}, {585, 1072764, 4644, 231}, {5052, 80161536, 40404, 1984}, {9573, 287864220, 76580, 3759},{191714, 115466138200, 1533700, 75286}, {13682428, 588133849050724, 109459412, 5373077}. No further terms up to 15*10^6. - _Giovanni Resta_, Jan 06 2014
%H A235230 New Scientist Magazine, <a href="http://www.newscientist.com/article/mg21328531.700-enigma-number-1686.html#.UslPmLQa4iM">Enigma #1686</a>, 22 February 2012.
%H A235230 Giovanni Resta, <a href="/A235230/a235230.pdf">Illustration for a(2) and a(3)</a>
%H A235230 Gregory V. Richardson, <a href="/A235230/a235230.txt">QuickBasic 64 program</a>
%e A235230 See picture in Links.
%o A235230 (QuickBASIC) ' See Links.
%K A235230 nonn,hard,more
%O A235230 1,2
%A A235230 _Gregory V. Richardson_, Jan 05 2014