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 A269007 #7 Jan 18 2019 06:33:16 %S A269007 5,36,305,2136,14240,91048,566656,3456320,20760192,123186784, %T A269007 723791744,4218132480,24414483712,140486492800,804321836032, %U A269007 4584741088256,26032741150720,147311358346752,831044097026048,4675403505475584 %N A269007 Number of n X 4 binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once. %H A269007 R. H. Hardin, <a href="/A269007/b269007.txt">Table of n, a(n) for n = 1..210</a> %F A269007 Empirical: a(n) = 12*a(n-1) - 40*a(n-2) + 8*a(n-3) + 92*a(n-4) - 32*a(n-5) - 64*a(n-6) for n>7. %F A269007 Empirical g.f.: x*(5 - 24*x + 73*x^2 - 124*x^3 + 60*x^4 + 16*x^5 + 4*x^6) / (1 - 6*x + 2*x^2 + 8*x^3)^2. - _Colin Barker_, Jan 18 2019 %e A269007 Some solutions for n=4: %e A269007 ..0..0..1..0. .1..0..1..0. .0..0..1..0. .0..1..0..0. .0..0..0..0 %e A269007 ..0..0..0..1. .1..0..0..0. .0..1..0..0. .0..1..0..1. .0..1..0..0 %e A269007 ..0..0..0..1. .0..1..0..1. .0..0..0..0. .1..0..0..0. .0..0..1..0 %e A269007 ..0..1..0..1. .0..0..0..0. .1..0..0..1. .0..0..0..1. .1..0..1..0 %Y A269007 Column 4 of A269011. %K A269007 nonn %O A269007 1,1 %A A269007 _R. H. Hardin_, Feb 17 2016