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 A094034 #16 Sep 20 2022 18:13:32
%S A094034 0,0,0,1,38,645,7510,71981,617358,4947685,37972070,283229661,
%T A094034 2072354878,14964711125,107078983830,761312910541,5388481567598,
%U A094034 38017703680965,267622831854790,1880882526962621,13203901505935518,92616363612417205
%N A094034 Number of connected 3-element antichains on a labeled n-set.
%H A094034 G. C. Greubel, <a href="/A094034/b094034.txt">Table of n, a(n) for n = 0..1000</a>
%H A094034 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (22,-190,820,-1849,2038,-840).
%F A094034 E.g.f.: (exp(7*x) - 6*exp(5*x) + 3*exp(4*x) + 14*exp(3*x) - 21*exp(2*x) + 11*exp(x) -2)/3!.
%F A094034 G.f.: -x^3*(5*x+1)*(56*x^2-11*x-1) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(7*x-1)). - _Colin Barker_, Nov 27 2012
%t A094034 With[{nmax = 50}, CoefficientList[Series[(Exp[7*x] - 6*Exp[5*x] + 3*Exp[4*x] + 14*Exp[3*x] - 21*Exp[2*x] + 11*Exp[x] - 2)/3!, {x, 0, nmax}], x] Range[0, nmax]!] (* _G. C. Greubel_, Oct 07 2017 *)
%t A094034 LinearRecurrence[{22,-190,820,-1849,2038,-840},{0,0,0,1,38,645,7510},30] (* _Harvey P. Dale_, Sep 20 2022 *)
%o A094034 (PARI) x='x+O('x^50); concat([0,0,0], Vec(-x^3*(5*x+1)*(56*x^2-11*x-1)/( (x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(7*x-1)))) \\ _G. C. Greubel_, Oct 07 2017
%Y A094034 Cf. A016269, A047707, A051112-A051118, A094033-A094037.
%K A094034 nonn,easy
%O A094034 0,5
%A A094034 Goran Kilibarda, _Vladeta Jovovic_, Apr 22 2004