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 A222512 #6 Jul 23 2025 02:42:07 %S A222512 0,11,35,84,423,1753,8489,39873,200999,988455,5011027,24887392, %T A222512 126164927,633230135,3213998827,16234077336,82517378821,418670560481, %U A222512 2132042077379,10852726670501,55367063804357,282538940546931,1443897042955709 %N A222512 Number of 4Xn 0..1 arrays with exactly floor(4Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..1 order. %C A222512 Row 4 of A222509 %H A222512 R. H. Hardin, <a href="/A222512/b222512.txt">Table of n, a(n) for n = 1..82</a> %e A222512 Some solutions for n=3 %e A222512 ..0..0..0....0..0..0....0..0..0....0..0..1....0..1..1....0..0..0....0..0..0 %e A222512 ..0..0..1....0..0..0....0..1..0....0..0..0....1..1..1....0..0..0....0..0..0 %e A222512 ..0..0..1....0..1..0....1..1..1....1..0..0....1..1..0....1..1..1....0..0..0 %e A222512 ..0..0..0....1..1..1....1..1..1....0..0..0....1..1..1....1..1..1....1..1..0 %K A222512 nonn %O A222512 1,2 %A A222512 _R. H. Hardin_ Feb 23 2013