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 A228881 #18 Nov 04 2024 01:33:23 %S A228881 1,2,3,4,5,6,7,8,8,9,10,10,13,14,14,13,16,17,12,14,8,12,20,15,19,20, %T A228881 26,22,25,26,27,28,22 %N A228881 Minimum number of spheres touching a wall of the container in the densest packing of n equal spheres into a cube. %C A228881 Spheres that are not part of the rigid framework, "rattlers", are always assumed not to touch the walls of the container cube. %C A228881 If optimal configurations can be obtained by taking away an arbitrary sphere from a configuration with a higher sphere count, a sphere touching the container wall is chosen. %H A228881 Hugo Pfoertner, <a href="http://www.randomwalk.de/sphere/incube/spheresincube.html">Densest Packing of Spheres in a Cube</a> (Java Visualization) %H A228881 Eckard Specht, <a href="http://hydra.nat.uni-magdeburg.de/packing/scu/scu.html">The best known packings of equal spheres in a cube</a>, (complete up to N = 1000). [The title should be "The best packings known ..."! - _N. J. A. Sloane_, Mar 23 2021] %e A228881 The first configuration in which there is an inner sphere not touching the walls occurs for n = 9, with 8 spheres in the corners of the cube and one sphere in the center of the cube. Therefore a(9) = 8. %Y A228881 Cf. A084824. %K A228881 nonn,more %O A228881 1,2 %A A228881 _Hugo Pfoertner_, Sep 13 2013 %E A228881 a(25)-a(33) from _Hugo Pfoertner_, Mar 23 2021