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 A051659 #19 Aug 29 2020 02:36:13 %S A051659 0,0,0,0,0,0,1,0,0,0,2,0,1,1,0,0,1,0,2,0,2,1,0,0,0,2,0,1,1,0,4,3,1,0, %T A051659 0,0,0,0,0,2,1,0,1,4,3,1 %N A051659 Experimental values for maximal number of "loose" circles in packing equal circles into a square. %D A051659 H. T. Croft, K. J. Falconer and R. K. Guy: Unsolved problems in geometry, Springer, New York, 1991. %H A051659 D. Boll, <a href="https://web.archive.org/web/20030211053857/http://www.frii.com/~dboll/packing.html">Optimal Packing Of Circles And Spheres</a> %H A051659 E. Friedman, <a href="https://erich-friedman.github.io/packing/index.html">Erich's Packing Center</a> %H A051659 C. D. Maranas, C. A. Floudas and P. M. Pardalos, <a href="https://doi.org/10.1016/0012-365x(93)e0230-2">New results in the packing of equal circles in a square</a>, Discrete Mathematics 142 (1995), p. 287-293. %H A051659 K. J. Nurmela and Patric R. J. Östergård, <a href="https://doi.org/10.1007/PL00009306">Packing up to 50 equal circles in a square</a>, Discrete Comput. Geom. 18 (1997) 1, p. 111-120. %H A051659 E. Specht, <a href="http://www.packomania.com/">www.packomania.com</a> %K A051659 nonn %O A051659 1,11 %A A051659 Eckard Specht (eckard.specht(AT)physik.uni-magdeburg.de) %E A051659 I do not know how many of these values have been rigorously proved. - _N. J. A. Sloane_