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 A222446 #6 Jul 23 2025 02:35:57 %S A222446 8,64,420,4056,32720,262104,2082688,16777216,134217728,1073741824, %T A222446 8588539008,68719476736,549755813888,4398046511104,35184256942080, %U A222446 281474976587776,2251799813537792,18014398509359104,144115179143299072 %N A222446 Sum of neighbor maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to the sum mod 4 of their horizontal, vertical and antidiagonal neighbors in a random 0..3 nX3 array. %C A222446 Column 3 of A222448 %H A222446 R. H. Hardin, <a href="/A222446/b222446.txt">Table of n, a(n) for n = 1..188</a> %e A222446 Some solutions for n=3 %e A222446 ..1..0..1....1..0..0....0..1..0....0..0..0....1..0..0....1..1..0....0..1..0 %e A222446 ..1..1..1....1..0..0....0..0..1....1..1..1....1..1..0....0..0..0....0..0..1 %e A222446 ..1..0..0....0..0..1....0..0..0....1..0..1....0..1..0....0..0..1....1..0..1 %K A222446 nonn %O A222446 1,1 %A A222446 _R. H. Hardin_ Feb 20 2013