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 A219138 #6 Jul 23 2025 00:15:51 %S A219138 7,39,281,1774,11385,73136,472638,3050285,19667721,126807809, %T A219138 817795362,5274346426,34015377046,219367395594,1414720693245, %U A219138 9123720789554,58840106012423,379467286876826,2447231592206585,15782503349398343 %N A219138 Unchanging value maps: number of nX4 binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 nX4 array. %C A219138 Column 4 of A219142 %H A219138 R. H. Hardin, <a href="/A219138/b219138.txt">Table of n, a(n) for n = 1..31</a> %e A219138 Some solutions for n=3 %e A219138 ..1..0..1..0....0..0..0..1....0..0..0..1....1..0..0..0....0..0..0..1 %e A219138 ..0..0..0..0....0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..0 %e A219138 ..0..1..0..1....1..1..0..0....0..0..0..1....1..0..1..0....0..0..1..0 %K A219138 nonn %O A219138 1,1 %A A219138 _R. H. Hardin_ Nov 12 2012