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 A379432 #5 Jan 14 2025 19:14:04 %S A379432 1,1,1,1,1,1,1,2,2,1,1,3,7,3,1,1,4,13,13,4,1,1,5,29,44,29,5,1,1,7,51, %T A379432 139,139,51,7,1,1,8,92,370,623,370,92,8,1,1,10,147,913,2307,2307,913, %U A379432 147,10,1,1,12,240,2048,7644,11673,7644,2048,240,12,1,1,14,357,4295,22344,50174,50174,22344,4295,357,14,1 %N A379432 Triangle read by rows: T(n,k) is the number of unsensed 2-connected (nonseparable) planar maps with n edges and k vertices, n >= 2, 2 <= k <= n. %C A379432 The maps considered here may include parallel edges. %C A379432 The number of faces is n + 2 - k. %H A379432 Timothy R. Walsh, <a href="/A007401/a007401.pdf">Number of sensed planar maps with n edges and m vertices</a>, pp. 29-36. %F A379432 T(n,k) = T(n, n+2-k). %e A379432 Triangle begins: %e A379432 1; %e A379432 1, 1; %e A379432 1, 1, 1; %e A379432 1, 2, 2, 1; %e A379432 1, 3, 7, 3, 1; %e A379432 1, 4, 13, 13, 4, 1; %e A379432 1, 5, 29, 44, 29, 5, 1; %e A379432 1, 7, 51, 139, 139, 51, 7, 1; %e A379432 1, 8, 92, 370, 623, 370, 92, 8, 1; %e A379432 1, 10, 147, 913, 2307, 2307, 913, 147, 10, 1; %e A379432 ... %Y A379432 Row sums are A006403. %Y A379432 Cf. A082680 (rooted), A342061 (sensed), A212438 (3-connected), A277741, A342060. %K A379432 nonn,tabl %O A379432 2,8 %A A379432 _Andrew Howroyd_, Jan 14 2025