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 A308578 #16 Jun 19 2019 00:49:36 %S A308578 0,1,1,4,5,9,10,16,20,25,30,36 %N A308578 Maximum number of non-overlapping circles of radius 1/n that can be placed inside a unit square. %C A308578 Alternatively described as the maximum number of circles of unit radius that can be placed inside a square of side length n. %C A308578 It appears that the terms a(2) to a(8) are equal to the related terms of A189889. %H A308578 E. Specht, <a href="http://hydra.nat.uni-magdeburg.de/packing/csq/csq.html">The Best Known Packings of Equal Circles in a Square</a> %F A308578 a(2k) = A084617(k). - _Jon E. Schoenfield_, Jun 09 2019 %e A308578 a(6)=9 because 9 circles of radius 1/6 can be placed in a 3 X 3 regular grid inside a unit square. %Y A308578 Cf. A189889, A084616, A084617. %K A308578 nonn,hard,more %O A308578 1,4 %A A308578 _Ethan D. Kidd_, Jun 08 2019