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 A220252 #6 Jul 23 2025 00:59:11 %S A220252 16,256,4096,45792,1048576,16777216,268435456,4294967296,68476059648, %T A220252 1099511627776,17592186044416,281474976710656,4503599627370496, %U A220252 72056280260730880,1152921504606846976,18446744073709551616 %N A220252 Sum of neighbor maps: number of nX4 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their king-move neighbors in a random 0..2 nX4 array. %C A220252 Column 4 of A220254 %H A220252 R. H. Hardin, <a href="/A220252/b220252.txt">Table of n, a(n) for n = 1..210</a> %e A220252 Some solutions for n=3 %e A220252 ..0..1..1..1....0..1..0..0....0..1..1..1....0..1..0..0....0..1..1..1 %e A220252 ..1..1..0..0....1..0..1..1....1..0..1..0....0..0..0..0....1..1..0..0 %e A220252 ..0..0..0..1....0..1..0..1....0..0..1..1....1..0..0..0....0..0..1..1 %K A220252 nonn %O A220252 1,1 %A A220252 _R. H. Hardin_ Dec 08 2012