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 A157220 #9 May 09 2018 23:01:30 %S A157220 3,2,4,2,6,2,4,2,6,2,8,2,6,4,4,2,6,2,8,4,6,2,6,2,6,2,4,2,12 %N A157220 Erroneous version of A304182. %H A157220 John S. Rutherford, <a href="http://dx.doi.org/10.1107/S010876730804333X">Sublattice enumeration. IV. Equivalence classes of plane sublattices by parent Patterson symmetry and colour lattice group type</a>, Acta Cryst. (2009). A65, 156-163. [See Table 4. Contains errors for n = 24 and 28.] %K A157220 dead %O A157220 2,1 %A A157220 _N. J. A. Sloane_, Feb 25 2009