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 A123811 #7 Feb 15 2025 15:32:53 %S A123811 1,1,73,893,11257,167129,1969619 %N A123811 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 8 which is symmetric after a rotation by 180 degrees. %Y A123811 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123811 nonn %O A123811 1,3 %A A123811 _Søren Eilers_, Oct 29 2006