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 A082787 #18 Feb 20 2024 02:32:44
%S A082787 2,60,6720,1663200,726485760,494010316800,482718652416000,
%T A082787 641171050071552000,1111363153457356800000,2436552577639909048320000,
%U A082787 6591982246414881207091200000,21572261901392698750205952000000,83992431415453295380032651264000000,383725422380885198036206312488960000000
%N A082787 a(n) = (2/3)*(2*n-1)!*binomial(3*n,2*n).
%C A082787 A solid 2-tree is a 2-tree embedded in three-dimensional space. That is, the faces of the triangles cannot interpenetrate themselves, so that there is a cyclic configuration of triangles around every edge. Bousquet and Lamathe showed the number of well-oriented edge-labeled solid 2-trees with 2n+1 edges is a(n). - _Allan Bickle_, Feb 19 2024
%H A082787 Allan Bickle, <a href="https://doi.org/10.20429/tag.2024.000105">A Survey of Maximal k-degenerate Graphs and k-Trees</a>, Theory and Applications of Graphs 0 1 (2024) Article 5.
%H A082787 M. Bousquet and C. Lamathe, <a href="https://doi.org/10.1016/j.disc.2004.11.015">Enumeration of solid trees according to edge number and edge degree distribution</a>, Discr. Math., 298 (2005), 115-141.
%t A082787 Table[(2(2n-1)!Binomial[3n,2n])/3,{n,20}] (* _Harvey P. Dale_, May 28 2014 *)
%K A082787 nonn
%O A082787 1,1
%A A082787 _N. J. A. Sloane_, May 22 2003