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 A270067 #6 Feb 06 2017 12:32:58 %S A270067 1,9,1371,148796,15913695,1707101599,184140417890,19823918037604, %T A270067 2133436326533143,229681994753502100,24725866354382952217, %U A270067 2661724100255128134369,286536699674194768262220,30845921492404301091244774,3320584102598070051873302366 %N A270067 Number of tilings of a 7 X n rectangle using monominoes and trominoes of any shape. %H A270067 Alois P. Heinz, <a href="/A270067/b270067.txt">Table of n, a(n) for n = 0..500</a> %H A270067 Wikipedia, <a href="https://en.wikipedia.org/wiki/Tromino">Tromino</a> %Y A270067 Column k=7 of A270061. %K A270067 nonn %O A270067 0,2 %A A270067 _Alois P. Heinz_, Mar 09 2016