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 A338947 #56 Jun 21 2022 14:58:50 %S A338947 1,3,6,3,6,6,6,6,3,6,12,3,6,6,6,6,6,12,6,6,9,6,12,6,12,3,6,6,6,6,6,6, %T A338947 12,12,12,6,3,6,6,6,12,6,12,3,6,6,12,12,6,6,18,6,6,12,6,6,9,12,6,6,6, %U A338947 12,12,6,6,9,6,12,6,6,12,12,6,6,12,6,12,6,6,6,12,12,3,12,6,6,24,6,12,6,3,12,6,6,12,6,6,12 %N A338947 Number of vertices of a hexagonal tessellation that lie on subsequent circles centered at a vertex of one hexagon. %C A338947 Radii of these circles are square roots of A003136. %C A338947 This is A113062 with zeros dropped. - _Andrey Zabolotskiy_, Jun 21 2022 %H A338947 Szymon Lukaszyk, <a href="https://www.researchgate.net/publication/345982332_A_short_note_about_the_geometry_of_graphene">A short note about the geometry of graphene</a>, ResearchGate, (2020). %H A338947 Szymon Lukaszyk, <a href="/A338947/a338947.pdf">Illustration of the subsequent 51 radii around a hexagon vertex</a>. %H A338947 S. Reich et al., <a href="https://www.ifkp.tu-berlin.de/fileadmin/i1/thomsen/publikationen/paper/290.pdf">Tight-binding description of graphene</a> (up to third-nearest neighbors circles). %Y A338947 Cf. A003136, A113062; A338992 (similar but with circles centered at the center of one hexagon); A104888, A106030, A317990 (terms multiplied by 3 in agreement for up to 17 term). %K A338947 nonn %O A338947 0,2 %A A338947 _Szymon Lukaszyk_, Nov 17 2020 %E A338947 a(0) changed from 0 to 1 by _Andrey Zabolotskiy_, Jun 21 2022