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 A006762 M3534 #26 Sep 06 2019 10:52:28
%S A006762 0,0,4,17,61,214,758,2723,9908,36444,135266,505859,1903888,7204872,
%T A006762 27394664,104592935,400795842,1540820540,5940738674,22964779658,
%U A006762 88983512781,345532572676,1344372335522,5239988770266,20457802016009,79992676367106,313224032098242,1228088671826971
%N A006762 Number of strictly 2-dimensional fixed polyominoes with n cells.
%C A006762 This sequence counts only polyominoes that are strictly 2-dimensional - it excludes those where all the squares are in a single line. Thus for n > 1, a(n) = A001168(n) - 2. - _Franklin T. Adams-Watters_, Jul 29 2007
%D A006762 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006762 Jean-François Alcover, <a href="/A006762/b006762.txt">Table of n, a(n) for n = 1..56</a>
%H A006762 W. F. Lunnon, <a href="https://doi.org/10.1093/comjnl/18.4.366">Counting multidimensional polyominoes</a>, Computer Journal 18 (1975), no. 4, pp. 366-367.
%F A006762 a(n) = A001168(n) - 2 for n > 1. - _Franklin T. Adams-Watters_, Jul 29 2007
%t A006762 A001168 = Cases[Import["https://oeis.org/A001168/b001168.txt", "Table"], {_, _}][[All, 2]];
%t A006762 a[n_] := If[n == 1, 0, A001168[[n]] - 2];
%t A006762 Array[a, 56] (* _Jean-François Alcover_, Sep 06 2019 *)
%Y A006762 A column of A195739.
%Y A006762 Cf. A001168.
%K A006762 nonn
%O A006762 1,3
%A A006762 _N. J. A. Sloane_
%E A006762 Name clarified and a(18)-a(28) from _Andrew Howroyd_, Dec 04 2018