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 A057766 #20 Apr 15 2023 12:27:14 %S A057766 1,2,6,20,60,210,756,2952,11565,46550,187803,763200,3101683,12627594, %T A057766 51398640,209268080,851834453,3467196936,14109860408,57413439000, %U A057766 233584274238,950220869136,3865081177744,15719992809672,63930676119100 %N A057766 Total area of all n-celled polyominoes. %H A057766 John Mason, <a href="/A057766/b057766.txt">Table of n, a(n) for n = 1..50</a> %H A057766 Andrew Clarke, <a href="http://www.recmath.com/PolyPages/PolyPages/Isopolyos.html">Isoperimetrical Polyominoes</a> [Link updated by _William Rex Marshall_, Dec 16 2009] %F A057766 a(n) = n*A000105(n). %K A057766 nonn %O A057766 1,2 %A A057766 _N. J. A. Sloane_, Nov 04 2000 %E A057766 More terms from _David Wasserman_, Oct 26 2003