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 A268795 #4 Feb 13 2016 13:43:15 %S A268795 96,652,3384,23994,168740,1158904,7801688,51781418,339641264, %T A268795 2206871084,14226779556,91107781858,580148670100,3676143046622, %U A268795 23194484120032,145793482383084,913349363853072,5704743147188222,35535874740219072 %N A268795 Number of nX5 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two exactly once. %C A268795 Column 5 of A268798. %H A268795 R. H. Hardin, <a href="/A268795/b268795.txt">Table of n, a(n) for n = 1..210</a> %F A268795 Empirical: a(n) = 2*a(n-1) +41*a(n-2) +54*a(n-3) -509*a(n-4) -2182*a(n-5) -2830*a(n-6) +1766*a(n-7) +7914*a(n-8) +2584*a(n-9) -10583*a(n-10) -6092*a(n-11) +11506*a(n-12) +5348*a(n-13) -11688*a(n-14) -620*a(n-15) +9251*a(n-16) -4462*a(n-17) -3137*a(n-18) +4774*a(n-19) -2365*a(n-20) +338*a(n-21) +198*a(n-22) -106*a(n-23) +12*a(n-24) +4*a(n-25) -a(n-26) for n>29 %e A268795 Some solutions for n=4 %e A268795 ..0..0..1..0..1. .2..2..1..2..1. .2..1..0..1..0. .0..1..0..0..0 %e A268795 ..1..0..1..0..0. .1..2..2..2..2. .1..0..0..0..0. .0..0..0..0..1 %e A268795 ..0..0..0..1..0. .1..2..2..2..1. .0..0..1..0..0. .0..1..0..0..1 %e A268795 ..1..0..0..0..0. .2..1..2..2..2. .1..0..0..0..0. .0..0..1..0..0 %Y A268795 Cf. A268798. %K A268795 nonn %O A268795 1,1 %A A268795 _R. H. Hardin_, Feb 13 2016