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 A094164 #19 Sep 08 2019 11:46:13
%S A094164 1,3,9,28,90,282,875,2700,8271,25265,77088,235014,716261,2182257,
%T A094164 6646200,20234080,61581327,187366482,569947883,1733389620,5270937735,
%U A094164 16025807017,48719131461,148092422604,450116618125,1367983011213,4157227183617
%N A094164 Number of rooted 2-dimensional polyominoes with n triangular cells, with no symmetries removed.
%D A094164 Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.
%H A094164 Jean-François Alcover, <a href="/A094164/b094164.txt">Table of n, a(n) for n = 1..32</a>
%H A094164 R. C. Schroeppel, <a href="http://www.experimentalmath.info/workshop2004/schroeppel-talk.pdf">A few mathematical experiments</a>, Experimental Mathematics Workshop, Oakland, 2004.
%F A094164 a(n) = n * A001420(n) / 2. - _Andrew Howroyd_, Dec 04 2018
%t A094164 A001420 = Cases[Import["https://oeis.org/A001420/b001420.txt", "Table"], {_, _}][[All, 2]];
%t A094164 a[n_] := n * A001420[[n]] / 2;
%t A094164 Array[a, 27] (* _Jean-François Alcover_, Sep 08 2019 *)
%Y A094164 A row of A094166.
%Y A094164 Cf. A001420.
%K A094164 nonn
%O A094164 1,2
%A A094164 _N. J. A. Sloane_, May 07 2004