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 A272906 #33 Nov 20 2017 21:35:25 %S A272906 1,1,2,5,19,130,1814 %N A272906 Number of topologically-distinct pizza slicings from n chords in general position. %C A272906 The problem is to cut a disk with n chords, no three of which may meet at a single strictly-interior point. For each such slicing, construct the graph on vertices (pieces of the pizza) connected by edges (line segments separating two pieces). a(n) gives the number of such graphs up to isomorphism. %C A272906 This is an empirical result, obtained from guided random trials. Independent programs agree up to and including a(5)=130. Term a(6)=1814 is unconfirmed. %C A272906 A054499, counting chord diagrams, is a loose lower bound. %H A272906 Jon Hart, <a href="/A272906/a272906_8.svg">2 configurations for n=2 cuts</a> %H A272906 Jon Hart, <a href="/A272906/a272906_9.svg">5 configurations for n=3 cuts</a> %H A272906 Jon Hart, <a href="/A272906/a272906_10.svg">19 configurations for n=4 cuts</a> %H A272906 Jon Hart, <a href="/A272906/a272906_11.svg">130 configurations for n=5 cuts</a> %e A272906 For n=3, there are a(3)=5 topologically distinct slicings from chords in general position. These exclude a sixth configuration found when the three chords meet at a point strictly internal to the pizza. %Y A272906 Cf. A273280. %Y A272906 Maximum number of regions, A000124(n), found in A090338(n) configurations. Minimum number of regions, n+1, found in A000055(n+1) configurations. Configurations can be partitioned by chord diagram, so A054499 is a (loose) lower bound. %K A272906 nonn,more %O A272906 0,3 %A A272906 _Jon Hart_, May 09 2016