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 A269664 #13 Feb 06 2017 12:24:09 %S A269664 1,1,153,58234,1895145,198253934,27438555522,1949314526229, %T A269664 193553900967497,20574308184277971,1830607857363940042, %U A269664 178792253082742021463,17735061025562799941630,1679378707647721857218932,163105210594579645492072521,15894545877032388610890500803 %N A269664 Number of tilings of a 12 X n rectangle with 4n trominoes of any shape. %H A269664 Alois P. Heinz, <a href="/A269664/b269664.txt">Table of n, a(n) for n = 0..100</a> %H A269664 Wikipedia, <a href="https://en.wikipedia.org/wiki/Tromino">Tromino</a> %Y A269664 Column k=12 of A233320. %Y A269664 Cf. A134438, A215826, A233290. %K A269664 nonn %O A269664 0,3 %A A269664 _Alois P. Heinz_, Mar 02 2016