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 A123782 #7 Feb 15 2025 15:25:32 %S A123782 23,679,27591,1227556,59212274,2990304700,156407426393 %N A123782 Number of ways to build a contiguous building with n LEGO blocks of size 1 X 4 on top of a fixed block of the same size. %C A123782 The base block is not counted among the n and must be the only block in the bottom layer of the building. %Y A123782 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123782 nonn,hard %O A123782 1,1 %A A123782 _Søren Eilers_, Oct 29 2006