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 A384850 #11 Jun 15 2025 14:39:26 %S A384850 1,0,1,0,0,1,0,0,1,2,0,0,0,2,3,0,0,0,1,7,6,0,0,0,1,7,22,12,0,0,0,0,5, %T A384850 42,76,27,0,0,0,0,2,49,237,271,65,0,0,0,0,1,35,442,1293,1001,175,0,0, %U A384850 0,0,0,18,510,3539,6757,3765,490 %N A384850 Triangle read by rows: T(n,k) is the number of unsensed simple planar maps with n edges and k vertices, 1 <= k <= n+1. %C A384850 The planar maps considered here are connected. %C A384850 The initial terms of this sequence can be computed using the tool "plantri", in particular the command "./plantri -u -v -c1 -p [n]" will compute values for a column. %H A384850 Andrew Howroyd, <a href="/A384850/b384850.txt">Table of n, a(n) for n = 0..135</a> (rows 0..15) %H A384850 Gunnar Brinkmann and Brendan McKay, <a href="http://users.cecs.anu.edu.au/~bdm/plantri/">Plantri (program for generation of certain types of planar graph)</a>. %e A384850 Triangle begins: %e A384850 1; %e A384850 0, 1; %e A384850 0, 0, 1; %e A384850 0, 0, 1, 2; %e A384850 0, 0, 0, 2, 3; %e A384850 0, 0, 0, 1, 7, 6; %e A384850 0, 0, 0, 1, 7, 22, 12; %e A384850 0, 0, 0, 0, 5, 42, 76, 27; %e A384850 0, 0, 0, 0, 2, 49, 237, 271, 65; %e A384850 0, 0, 0, 0, 1, 35, 442, 1293, 1001, 175; %e A384850 ... %Y A384850 Row sums are A006395. %Y A384850 Column sums are A372892. %Y A384850 Main diagonal is A006082. %Y A384850 Subdiagonal is A384967. %Y A384850 Cf. A054923 (graphs), A277741 (not necessarily simple), A342060 (2-connected), A212438 (3-connected), A384963 (version by number of vertices then faces). %K A384850 nonn,tabl %O A384850 0,10 %A A384850 _Andrew Howroyd_, Jun 13 2025