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 A269958 #9 Feb 06 2017 12:29:26 %S A269958 1,1173,5271923,30860212081,193553900967497,1235348565576072999, %T A269958 7918615596845276941783,50812059004074711375396005, %U A269958 326133836808482000144440191279,2093399184722452211913343015136793,13437387174568575272118729720355720407 %N A269958 Number of tilings of an 8 X 3n rectangle using 8n trominoes of any shape. %H A269958 Alois P. Heinz, <a href="/A269958/b269958.txt">Table of n, a(n) for n = 0..262</a> %H A269958 Wikipedia, <a href="https://en.wikipedia.org/wiki/Tromino">Tromino</a> %Y A269958 Trisection of column k=8 of A233320. %K A269958 nonn %O A269958 0,2 %A A269958 _Alois P. Heinz_, Mar 08 2016