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 A296506 #28 Jan 02 2019 12:57:17 %S A296506 1,280,833712928048000000 %N A296506 Number of generalized knockout tournament seedings with 3 players in each match and n rounds. %C A296506 Next term is too large to include. %H A296506 Alexander Karpov, <a href="https://wp.hse.ru/data/2017/12/12/1160180715/WP7_2017_03_________.pdf">Generalized knockout tournaments</a>, National Research University Higher School of Economics. WP7/2017/03. %H A296506 Alexander Karpov, <a href="/A296506/a296506.pdf">Generalized knockout tournaments</a>. %F A296506 a(n) = (3^n)!/6^((3^n-1)/2). %t A296506 f[n_] := (3^n)!/6^((3^n - 1)/2); Array[f, 3] (* _Robert G. Wilson v_, Dec 27 2017 *) %Y A296506 Cf. A067667 (number of knockout tournament seedings with two players in each match). %K A296506 nonn %O A296506 1,2 %A A296506 _Alexander Karpov_, Dec 13 2017