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 A333280 #25 May 29 2021 07:05:57 %S A333280 28,92,296,652,1408,2470,4312,6774,10428,14992,21492,29328,39876, %T A333280 52184,67616,85588,108192,133674,164992,200158,241560,287428,341768, %U A333280 401472,470764,546230,632404,726170,833420,948550,1079204,1220054,1376552,1543742,1729000 %N A333280 Column 2 of triangle in A333278. %C A333280 For the graphs defined in A331452 and A288187 only the counts for graphs that are one square wide have formulas for regions, edges, and vertices (see A306302, A331757, A331755). For width 2 there are six such sequences (A331766, A331765, A331763; A333279, A333280, A333281). It would be nice to have a formula for any one of them. %C A333280 See A333279 for illustrations. %H A333280 Lars Blomberg, <a href="/A333280/b333280.txt">Table of n, a(n) for n = 1..200</a> %H A333280 Hugo Pfoertner, <a href="/A288177/a288177.pdf">Illustrations of Chamber Complexes up to 5 X 5</a>. %Y A333280 Cf. A331452, A288187; A331766, A331765, A331763; A333279, A333280, A333281. %K A333280 nonn %O A333280 1,1 %A A333280 _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 15 2020 %E A333280 a(10) and beyond from _Lars Blomberg_, May 23 2021