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 A291809 #10 Sep 03 2017 21:59:30 %S A291809 1,2,35,6563 %N A291809 Number of tilings of n X n square using differently sized polyominoes. %C A291809 The sequence gives the number of distinct tilings by polyominoes of a square with side n, considering tilings that are formed by polyominoes of all different sizes. As for "free" polyominoes, tilings that are reflections or rotations of each other are not considered distinct. %H A291809 John Mason, <a href="/A291809/a291809_1.pdf">Tiling examples</a> %Y A291809 Cf. A268416 (polyominoes that will fit in n-sided square), A291806 (polyomino tilings of square), A291807 (symmetric tilings), A291808 (tilings with distinct polyominoes). %K A291809 nonn,more %O A291809 1,2 %A A291809 _John Mason_, Sep 01 2017