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 A123829 #9 Feb 15 2025 15:21:17 %S A123829 1,2,44,185,3276,15682,282377,1480410,26264942 %N A123829 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 4 which is symmetric after a rotation by 180 degrees. %H A123829 <a href="/wiki/Index_to_OEIS:_Section_Lc#LEGO">Index entry for sequences related to LEGO blocks</a> %Y A123829 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123829 nonn %O A123829 1,2 %A A123829 _Søren Eilers_, Oct 29 2006