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 A322500 #4 Dec 12 2018 10:54:01 %S A322500 1,1,21,257,2989,34468,396500,4577274,52338705,600923375,6897569624, %T A322500 79170705722,908721438900,10430285080567,119719520002653, %U A322500 1374133015203548,15772280213569812,181033948036338279,2077904397828614231,23850149155575310594,273751580233289217307 %N A322500 Number of tilings of a 7 X n rectangle using V (2m+1)-ominoes (m >= 0) in standard orientation. %C A322500 The shapes of the tiles are: %C A322500 ._. %C A322500 ._. | | %C A322500 ._. | | | | %C A322500 ._. | |_. | |_._. | |_._._. %C A322500 |_| |___| |_____| |_______| ... . %H A322500 Alois P. Heinz, <a href="/A322500/b322500.txt">Table of n, a(n) for n = 0..944</a> %H A322500 Wikipedia, <a href="https://en.wikipedia.org/wiki/Polyomino">Polyomino</a> %Y A322500 Column k=7 of A322494. %K A322500 nonn %O A322500 0,3 %A A322500 _Alois P. Heinz_, Dec 12 2018