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 A046091 #30 Feb 16 2025 08:32:38
%S A046091 1,1,1,3,5,12,30,79,227,709,2318,8049,29372,112000,444855,1833072,
%T A046091 7806724,34252145,154342391,712231465,3357126655,16119421175,
%U A046091 78580665333
%N A046091 Number of connected planar graphs with n edges.
%C A046091 Inverse Euler transform of A343872. - _Andrew Howroyd_, May 05 2021
%H A046091 B. D. McKay and A. Piperno, <a href="http://dx.doi.org/10.1016/j.jsc.2013.09.003">Practical Graph Isomorphism</a>, II, J. Symbolic Computation, 60 (2014), pp. 94-112.
%H A046091 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PlanarConnectedGraph.html">Planar Connected Graph.</a>
%e A046091 a(3) = 3 since the three connected graphs with three edges are a path, a triangle and a "Y".
%e A046091 The first difference between this sequence and A002905 is for n=9 edges where we see K_{3,3}, the "utility graph".
%o A046091 (nauty)
%o A046091 # count graphs for the sequence by number of vertices v, sum over v afterwards
%o A046091 geng -c $v $n:$n | planarg -q | countg -q # _Georg Grasegger_, Jul 06 2023
%Y A046091 Row sums of A343873.
%Y A046091 Column sums of A049334.
%Y A046091 Cf. A002905, A003094, A066951, A291842, A343869, A343872.
%K A046091 nonn,nice,hard,more
%O A046091 0,4
%A A046091 _Brendan McKay_
%E A046091 a(11)-a(19) from _Martin Fuller_ using nauty by _Brendan McKay_, Mar 07 2015
%E A046091 a(20)-a(22) added by _Georg Grasegger_, Jul 06 2023