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 A280855 #4 Jan 09 2017 09:34:55 %S A280855 11,110,96,124,216,462,1005,2010,3907,7756,15749,31804,63463,126758, %T A280855 254453,511180,1024877,2052836,4115191,8254198,16552251,33182160, %U A280855 66522097,133381078,267442273,536212952,1075064777,2155474072,4321733703 %N A280855 Number of nX4 0..2 arrays with no element equal to more than one of its king-move neighbors and with new values introduced in order 0 sequentially upwards. %C A280855 Column 4 of A280859. %H A280855 R. H. Hardin, <a href="/A280855/b280855.txt">Table of n, a(n) for n = 1..210</a> %F A280855 Empirical: a(n) = a(n-1) +a(n-2) +a(n-3) +2*a(n-4) +3*a(n-5) -4*a(n-6) -3*a(n-7) -4*a(n-10) +2*a(n-12) for n>16 %e A280855 Some solutions for n=4 %e A280855 ..0..1..1..0. .0..1..0..1. .0..1..2..2. .0..1..1..2. .0..1..1..2 %e A280855 ..2..0..2..0. .0..2..0..2. .2..1..0..1. .0..2..0..0. .0..2..0..2 %e A280855 ..2..1..2..1. .1..2..1..2. .2..0..2..1. .1..2..1..2. .2..1..0..1 %e A280855 ..0..1..0..1. .1..0..1..0. .1..1..2..0. .1..0..1..2. .0..1..2..1 %Y A280855 Cf. A280859. %K A280855 nonn %O A280855 1,1 %A A280855 _R. H. Hardin_, Jan 09 2017