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 A123774 #7 Feb 15 2025 15:23:28 %S A123774 14,244,5762,147801,4117161,119893930,3616711327,111950012510, %T A123774 3536272532516 %N A123774 Number of ways to build a contiguous building with n LEGO blocks of size 1 X 3 on top of a fixed block of the same size. %C A123774 The base block is not counted among the n and must be the only block in the bottom layer of the building. %Y A123774 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123774 nonn,hard %O A123774 1,1 %A A123774 _Søren Eilers_, Oct 29 2006