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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.

A245246 Number of ways to delete an edge (up to the outcome) in the simple unlabeled graphs on n nodes.

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%I A245246 #13 Oct 13 2016 09:46:57
%S A245246 0,1,3,14,74,571,6558,125066,4147388
%N A245246 Number of ways to delete an edge (up to the outcome) in the simple unlabeled graphs on n nodes.
%C A245246 Also, the number of distinct pairs (G,H) of simple unlabeled graphs on n nodes, where H can be obtained from G by deletion of a single edge.
%C A245246 For n<6, we have a(n) = A126122(n), since the non-isomorphic edges in a graph on n<6 nodes uniquely define the result of their deletion. However, there is a graph on 6 nodes (see link below) with two non-isomorphic edges, deletion of either of which results in the same graph. Hence, for n>=6, a(n) < A126122(n).
%H A245246 Max Alekseyev, <a href="/A245246/a245246.png">Example of the graph on 6 nodes</a>, where deletion of red or blue edge (which are non-isomorphic) results in the same graph.
%H A245246 Max Alekseyev et al., <a href="http://mathoverflow.net/q/176215">Removal of non-isomorphic edges results in the same graph</a>, MathOverflow, 2014.
%Y A245246 Cf. A000088, A126122
%K A245246 nonn,more
%O A245246 1,3
%A A245246 _Max Alekseyev_, Jul 15 2014