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 A218838 #8 Mar 10 2018 07:15:19 %S A218838 7,57,453,3617,28888,230726,1842766,14717828,117548611,938839259, %T A218838 7498337380,59887849061,478313295496,3820200795065,30511244937310, %U A218838 243687732023270,1946289338913085,15544656923507264,124152331330394548 %N A218838 Unmatched value maps: number of n X 4 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 n X 4 array. %C A218838 Column 4 of A218842. %H A218838 R. H. Hardin, <a href="/A218838/b218838.txt">Table of n, a(n) for n = 1..210</a> %F A218838 Empirical: a(n) = 7*a(n-1) + 5*a(n-2) + 24*a(n-3) - 9*a(n-4) + 9*a(n-5) for n>6. %F A218838 Empirical g.f.: x*(7 + 8*x + 19*x^2 - 7*x^3 - x^4 + 3*x^5) / (1 - 7*x - 5*x^2 - 24*x^3 + 9*x^4 - 9*x^5). - _Colin Barker_, Mar 10 2018 %e A218838 Some solutions for n=3: %e A218838 ..0..0..0..0....1..1..0..0....1..0..0..0....1..1..0..0....1..0..0..1 %e A218838 ..1..0..1..1....1..0..0..1....1..0..0..0....1..0..0..0....0..0..1..1 %e A218838 ..1..1..0..0....1..0..0..0....0..0..1..1....1..0..1..1....1..1..1..1 %Y A218838 Cf. A218842. %K A218838 nonn %O A218838 1,1 %A A218838 _R. H. Hardin_, Nov 07 2012