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 A222578 #5 Jul 23 2025 02:47:35 %S A222578 122,200,5210,50535,881766,14120189,278335019,5890042566,140281638242 %N A222578 Number of 6Xn 0..2 arrays with no more than floor(6Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..2 order. %C A222578 Row 6 of A222573 %e A222578 Some solutions for n=3 %e A222578 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1 %e A222578 ..1..0..2....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0 %e A222578 ..2..0..2....0..0..0....0..0..0....0..0..0....1..0..0....0..0..0....0..0..0 %e A222578 ..2..2..2....0..0..1....0..0..0....1..0..0....1..0..0....1..0..2....0..0..0 %e A222578 ..2..2..2....1..1..1....1..1..0....0..0..2....2..0..0....2..0..0....0..0..1 %e A222578 ..2..2..2....1..1..0....0..2..0....2..0..1....0..0..2....2..0..0....2..0..2 %K A222578 nonn %O A222578 1,1 %A A222578 _R. H. Hardin_ Feb 25 2013