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 A219306 #6 Jul 23 2025 00:21:53 %S A219306 7,51,423,3334,25647,200376,1574278,12334824,96480571,755212375, %T A219306 5914093280,46306103745,362524633360,2838264260603,22221912955624, %U A219306 173982894127917,1362160216940837,10664747935404835,83497581682654109 %N A219306 Unchanging value maps: number of nX4 binary arrays indicating the locations of corresponding elements unequal to no horizontal or vertical neighbor in a random 0..2 nX4 array. %C A219306 Column 4 of A219310 %H A219306 R. H. Hardin, <a href="/A219306/b219306.txt">Table of n, a(n) for n = 1..48</a> %e A219306 Some solutions for n=3 %e A219306 ..1..0..0..0....1..0..0..0....0..0..0..1....0..1..0..1....1..0..1..1 %e A219306 ..1..0..0..0....0..1..0..1....1..0..0..1....0..0..0..0....0..0..0..1 %e A219306 ..1..0..0..0....0..0..0..0....0..0..0..1....0..1..0..1....0..1..0..0 %K A219306 nonn %O A219306 1,1 %A A219306 _R. H. Hardin_ Nov 17 2012