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 A291808 #12 Sep 03 2017 21:59:21 %S A291808 1,2,44,10066 %N A291808 Number of tilings of an n X n square using distinct polyominoes. %C A291808 The sequence gives the number of distinct tilings by polyominoes of a square with side n, considering tilings that are formed of distinct polyominoes. As for "free" polyominoes, tilings that are reflections or rotations of each other are not considered distinct. %H A291808 John Mason, <a href="/A291808/a291808_2.pdf">Example tilings</a> %Y A291808 Cf. A268416 (polyominoes that will fit in n-sided square), A291806 (polyomino tilings of square), A291807 (symmetric tilings), A291809 (tilings with differently sized polyominoes). %K A291808 nonn,more %O A291808 1,2 %A A291808 _John Mason_, Sep 01 2017