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 A123800 #8 Jul 21 2017 13:16:17 %S A123800 11,136,1991,30701,500038,8346595,142812582,2481290457,43703296703 %N A123800 Number of ways to build a contiguous building with n LEGO blocks of size 1 X 6 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position. %C A123800 The base block is not counted among the n and must be the only block in the bottom layer of the building. %Y A123800 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123800 nonn,hard %O A123800 1,1 %A A123800 _Søren Eilers_, Oct 29 2006