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 A232722 #17 Feb 07 2017 16:59:55 %S A232722 1,64,796558,2569437089,14571957312254,72713560548906621, %T A232722 384821695402098361211,2010131712836219582393758, %U A232722 10562717745357186307808646827,55429948254413509959115263015669,291053238120184913211835376456587574,1528063805458061047577398579978736135916 %N A232722 Number of tilings of a 10 X 2n rectangle with 5n tetrominoes of any shape. %H A232722 Alois P. Heinz, <a href="/A232722/b232722.txt">Table of n, a(n) for n = 0..20</a> %H A232722 S. Butler, J. Ekstrand, S. Osborne, <a href="/A230031/a230031.pdf">TETRIS Tiling</a>, AMS Spring Central Sectional, Iowa State University, April 27-28 2013 %H A232722 Wikipedia, <a href="https://en.wikipedia.org/wiki/Tetris">Tetris</a> %H A232722 Wikipedia, <a href="https://en.wikipedia.org/wiki/Tetromino">Tetromino</a> %Y A232722 Cf. A174248, A232684, A232698. %Y A232722 Even bisection of column k=10 of A230031. %K A232722 nonn %O A232722 0,2 %A A232722 _Alois P. Heinz_, Nov 28 2013