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 A129933 #7 Jun 09 2023 23:18:53
%S A129933 1,2,12,840,1663200,174356582400,1561112121913344000,
%T A129933 1754317855900734514790400000,341362923889542287855059017400320000000,
%U A129933 15163751542692044063740921044974247390216192000000000,195932150519417838363658963697014150610807423633478962380800000000000
%N A129933 a(n) = (n*(n+1)/2+1)!/n!.
%t A129933 Table[(n (n+1)/2+1)!/n!,{n,0,20}] (* _Harvey P. Dale_, Aug 04 2022 *)
%Y A129933 Cf. A000124, A107868, A129893.
%K A129933 nonn
%O A129933 0,2
%A A129933 _N. J. A. Sloane_, Jun 06 2007