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 A321589 #6 Nov 19 2018 11:00:45 %S A321589 1,1,13,83,1103,11453,127320,1388914,15330926,167842605,1845273115, %T A321589 20252779428,222470481108,2442643290488,26825729083460, %U A321589 294573090471640,3234887436123961,35523266398630041,390097222479871444,4283805079495347243,47042252237178793997 %N A321589 Number of tilings of a 6 X n rectangle using pentominoes of shapes X, Y, T and dominoes. %H A321589 Alois P. Heinz, <a href="/A321589/b321589.txt">Table of n, a(n) for n = 0..962</a> %H A321589 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a> %Y A321589 Cf. A286347. %K A321589 nonn %O A321589 0,3 %A A321589 _Alois P. Heinz_, Nov 13 2018