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 A123797 #12 Sep 12 2018 05:30:11 %S A123797 1,1,7,10,88,142,1277,2193,19967,35449,325809,593589,5473435,10159187, %T A123797 93929982,176846933 %N A123797 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 6 which is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees. %Y A123797 Cf. A112389, A123762 - A123827, A123829 - A123849. %K A123797 nonn,more %O A123797 1,3 %A A123797 _Søren Eilers_, Oct 29 2006 %E A123797 More terms by _Søren Eilers_, Sep 12 2018