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 A218818 #7 Jun 20 2021 20:29:25 %S A218818 1,11,195,8961,1229783,468783431 %N A218818 Unmatched value maps: number of n X n binary arrays indicating the locations of corresponding elements not equal to any king-move neighbor in a random 0..2 n X n array. %e A218818 Some solutions for n=3 %e A218818 ..1..0..0....0..0..1....1..1..0....0..0..0....0..0..1....1..1..0....0..0..1 %e A218818 ..1..0..0....0..0..1....0..0..1....0..0..0....0..0..0....0..0..0....1..0..1 %e A218818 ..0..1..1....0..0..0....0..0..0....0..0..1....1..1..0....0..1..0....0..1..0 %Y A218818 Diagonal of A218823. %K A218818 nonn %O A218818 1,2 %A A218818 _R. H. Hardin_, Nov 06 2012