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 A186216 #6 May 27 2021 13:55:02 %S A186216 76263,20738153,2259545215,363322785761,49524283508081 %N A186216 Number of (n+1) X 7 0..2 arrays with every 2 X 2 subblock determinant equal to some horizontal or vertical neighbor 2 X 2 subblock determinant. %C A186216 Column 6 of A186218. %e A186216 Some solutions for 3 X 7 %e A186216 ..0..0..0..0..1..2..2....0..0..2..2..1..2..2....0..0..0..0..2..0..2 %e A186216 ..0..0..0..0..1..1..2....0..0..0..0..0..0..0....0..0..0..0..0..0..1 %e A186216 ..0..0..0..0..1..0..2....0..0..0..2..2..1..2....0..0..1..1..2..0..1 %Y A186216 Cf. A186218. %K A186216 nonn %O A186216 1,1 %A A186216 _R. H. Hardin_ Feb 15 2011