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 A193179 #8 Mar 30 2012 16:52:03 %S A193179 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,1,3,1,2,9,1,9,17,1,32, %T A193179 1,3,34,19,2,5,121,1,211,55,1,201,695,32,43 %N A193179 Number of classes of two-dimensional generalized Bravais lattices with 2n-fold symmetry. %C A193179 Related to class numbers of cyclotomic fields, although the precise relationship is not clear to me. Compare A000927. %D A193179 Mermin, N. David; Rokhsar, Daniel S.; and Wright, David C.; Beware of 46-fold symmetry: the classification of two-dimensional quasicrystallographic lattices. Phys. Rev. Lett. 58 (1987), 2099-2101. %Y A193179 See A193175 for values of 2n such that a(n) = 1. %Y A193179 Cf. A000927. %K A193179 nonn %O A193179 2,22 %A A193179 _N. J. A. Sloane_, Jul 17 2011