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 A281778 #20 Aug 03 2021 15:29:36
%S A281778 0,0,0,0,24,900,18030,276570,3680964,45065160,523292010,5859909990,
%T A281778 63862084704,680829769620,7122705252390,73284607133010,
%U A281778 742843170653244,7429450873589280,73416173732059170,717721593866613630,6949589106333898584,66721599431782204140
%N A281778 Number of distinct topologies on an n-set that have exactly 10 open sets.
%H A281778 Colin Barker, <a href="/A281778/b281778.txt">Table of n, a(n) for n = 0..1000</a>
%H A281778 Moussa Benoumhani, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL9/Benoumhani/benoumhani11.html">The Number of Topologies on a Finite Set</a>, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.6.
%H A281778 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (45,-870,9450,-63273,269325,-723680,1172700,-1026576,362880).
%F A281778 a(n) = 4! Stirling2(n, 4) + 11/2*5! Stirling2(n, 5) + 73/8*6! Stirling2(n, 6) + 15/2*7! Stirling2(n, 7) + 7/2*8! Stirling2(n, 8) + 9! Stirling2(n, 9).
%F A281778 G.f.: (6*(4 - 30*x - 265*x^2 + 3570*x^3 - 10839*x^4 + 22680*x^5))*x^4/Product_{j=1..9} (1-j*x). - _Robert Israel_, Jan 29 2017
%o A281778 (PARI) concat(vector(4), Vec(6*x^4*(4 - 30*x - 265*x^2 + 3570*x^3 - 10839*x^4 + 22680*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)*(1 - 7*x)*(1 - 8*x)*(1 - 9*x)) + O(x^30))) \\ _Colin Barker_, Jan 30 2017
%Y A281778 The number of distinct topologies on an n-set with exactly k open sets for k=2..12 is given by A000012, A000918, A281773, A028244, A281774, A281775, A281776, A281777,A281778, A281779, A281780.
%K A281778 nonn,easy
%O A281778 0,5
%A A281778 Submitted on behalf of Moussa Benoumhani by _Geoffrey Critzer_, Jan 29 2017