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 A122836 #7 Jan 01 2020 04:21:06
%S A122836 0,0,0,10,243,6131,202503,9464302,641960602,63249658532,8976900501699,
%T A122836 1816843604787333,519355528928422629,207881392866381430470,
%U A122836 115617051961092253351796,88736269118240819706018342,93411113411702066083187522063,134137950093337685116171325021995,261492535743634369726764132015849219
%N A122836 Number of topologies on n labeled elements in which at least one element belongs to some pair of noncomparable members of the topology.
%C A122836 See comments in A122835.
%D A122836 J. Munkres, Topology, Prentice Hall, (2000), p. 76.
%t A122836 A000798 = Cases[Import["https://oeis.org/A000798/b000798.txt", "Table"], {_, _}][[All, 2]];
%t A122836 a122835[n_] := (3/4)*(PolyLog[-n, 1/2] + Boole[n == 0]) - 1/2;
%t A122836 a[n_] := A000798[[n + 1]] - a122835[n];
%t A122836 a /@ Range[0, 18] (* _Jean-François Alcover_, Jan 01 2020, after _Michael Somos_ in A122835 *)
%Y A122836 a(n) = A000798(n) - A122835(n).
%K A122836 hard,nice,nonn
%O A122836 0,4
%A A122836 Nathan K. McGregor (mcgregnk(AT)ese.wustl.edu), Sep 15 2006
%E A122836 a(13) corrected and a(16)-a(18) by _Jean-François Alcover_, Jan 01 2020