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 A123804 #7 Jul 21 2017 15:39:52 %S A123804 1,7,109,1877,35243,685817,13719483,279714347,5788634457 %N A123804 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 7 which is flat, i.e., with all blocks in parallel position. %Y A123804 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123804 nonn,hard %O A123804 1,2 %A A123804 _Søren Eilers_, Oct 29 2006