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 A377785 #24 Nov 25 2024 16:29:08 %S A377785 1,2,5,19,80,407,2403,15570,107366,773660,5746826,43693041,338367370, %T A377785 2660629311,21193182914,170714892489,1388711749891,11395477091396, %U A377785 94238431709661,784796579069288,6576997589788217,55435506835745851,469698698872829672,3998806331800289798 %N A377785 Number of n-node connected unsensed planar maps with an external face in which all internal faces are triangles. %C A377785 Maps for a(3) through a(7) are illustrated in Links. %C A377785 The planar maps considered are without loops or isthmuses. %C A377785 In other words, a(n) is the number of embeddings in the plane of connected bridgeless planar simple graphs with n vertices in which each internal face is a triangle. %H A377785 Andrew Howroyd, <a href="/A377785/b377785.txt">Table of n, a(n) for n = 3..200</a> %H A377785 Ya-Ping Lu, <a href="/A377785/a377785.pdf">Illustration of initial terms</a> %F A377785 a(n) = (A378335(n) + A378339(n))/2. - _Andrew Howroyd_, Nov 24 2024 %o A377785 (PARI) A377785seq(30) \\ See PARI link in A378340 for program code. %Y A377785 Row sums of A378103. %Y A377785 Cf. A005027 (2-connected), A342056 (3-connected), A378335 (sensed), A378339 (achiral), A378340. %K A377785 nonn %O A377785 3,2 %A A377785 _Ya-Ping Lu_, Nov 06 2024 %E A377785 a(9) onwards from _Andrew Howroyd_, Nov 24 2024