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 A006406 M1195 #30 Jan 17 2025 02:34:05
%S A006406 1,1,2,4,9,24,81,274,1071,4357,18416,80040,356109,1610910,7399114
%N A006406 Number of sensed 2-connected simple planar maps with n edges.
%C A006406 A simple planar map is a planar map without loops or parallel edges.
%C A006406 Equivalently, a(n) is the number of embeddings on the sphere of 2-connected planar graphs with n edges up to orientation preserving isomorphisms. - _Andrew Howroyd_, Mar 27 2021
%D A006406 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006406 Timothy R. Walsh, <a href="http://dx.doi.org/10.1137/0604018">Generating nonisomorphic maps without storing them</a>, SIAM J. Algebraic Discrete Methods 4 (1983), no. 2, 161-178.
%F A006406 a(n) = Sum_{k=3..n} A342059(k, n+2-k). - _Andrew Howroyd_, Mar 27 2021
%Y A006406 Cf. A006402, A006404, A006407 (unsensed case), A342059, A379437 (rooted).
%K A006406 nonn,more
%O A006406 3,3
%A A006406 _N. J. A. Sloane_
%E A006406 a(11) and a(12) from _Sean A. Irvine_, Apr 02 2017
%E A006406 a(13)-a(17) from _Andrew Howroyd_, Mar 27 2021