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 A218760 #6 Jul 23 2025 00:03:31 %S A218760 4,18,90,403,1876,8697,40383,187413,869598,4035492,18727387,86907272, %T A218760 403304737,1871588753,8685363409,40305616278,187043701224, %U A218760 868001747571,4028080274884,18692855005565,86746738864403,402560052640421 %N A218760 Unmatched value maps: number of nX3 binary arrays indicating the locations of corresponding elements not equal to any horizontal or vertical neighbor in a random 0..1 nX3 array. %C A218760 Column 3 of A218765 %H A218760 R. H. Hardin, <a href="/A218760/b218760.txt">Table of n, a(n) for n = 1..63</a> %F A218760 Empirical: a(n) = 4*a(n-1) +a(n-2) +7*a(n-3) +11*a(n-4) +2*a(n-5) -28*a(n-6) -11*a(n-7) -4*a(n-8) -13*a(n-9) +12*a(n-10) -137*a(n-11) -48*a(n-12) +129*a(n-13) +31*a(n-14) -51*a(n-15) -32*a(n-16) +6*a(n-17) +10*a(n-18) +2*a(n-19) %e A218760 Some solutions for n=3 %e A218760 ..1..0..1....1..0..1....0..0..0....0..1..0....0..0..1....1..0..0....0..0..0 %e A218760 ..0..0..0....0..0..0....1..0..0....0..0..0....0..1..1....1..0..0....0..1..0 %e A218760 ..0..1..0....1..0..0....1..1..1....0..0..1....1..1..1....1..1..0....1..1..1 %K A218760 nonn %O A218760 1,1 %A A218760 _R. H. Hardin_ Nov 05 2012