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 A220251 #6 Jul 23 2025 00:59:05 %S A220251 8,48,324,4096,31744,262144,2011776,16728064,134217728,1073741824, %T A220251 8557195616,68719476736,549755813888,4397962625024,35175111229440, %U A220251 281474976710656,2251796592459776,18014398509481984,144112331924652032 %N A220251 Sum of neighbor maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their king-move neighbors in a random 0..2 nX3 array. %C A220251 Column 3 of A220254 %H A220251 R. H. Hardin, <a href="/A220251/b220251.txt">Table of n, a(n) for n = 1..210</a> %e A220251 Some solutions for n=3 %e A220251 ..1..0..1....1..0..0....0..0..0....0..1..0....0..1..0....0..0..0....0..0..0 %e A220251 ..1..1..0....0..0..1....1..0..1....0..0..0....0..1..0....1..0..0....1..0..0 %e A220251 ..1..1..1....0..0..0....0..0..0....0..0..1....0..1..1....1..0..0....0..1..1 %K A220251 nonn %O A220251 1,1 %A A220251 _R. H. Hardin_ Dec 08 2012