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 A120991 #12 Nov 11 2023 01:16:51 %S A120991 0,0,1,1,9,12,39,61,178,274,796,1251,3578,5692,16290,26069,74980, %T A120991 120676,348564,563503,1635175,2652445,7729807,12574028,36784467, %U A120991 59975232,176063801,287613473,846967739,1385815492,4092516853,6705360813,19852731854,32565589836,96642900684 %N A120991 Number of free hexagonal polygons of symmetry class C_(2v) and area n. %H A120991 Markus Vöge, Anthony J. Guttmann and Iwan Jensen, <a href="https://doi.org/10.1021/ci010098g">On the number of benzenoid hydrocarbons</a>, J. Chem. Inf. Comput. Sci., (2002), vol. 42, 456-466. See Table 3 under the column C_(2c) [sic. This is a typo, should be C_(2v) instead]. %K A120991 nonn %O A120991 1,5 %A A120991 _Parthasarathy Nambi_, Aug 19 2006 %E A120991 More terms from _N. J. A. Sloane_, Aug 27 2006 %E A120991 Name corrected by _Andrey Zabolotskiy_, Nov 10 2023