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 A265864 #6 Aug 12 2016 06:53:59 %S A265864 2,22,152,1462,13772,139144,1431824,15086614,161254844,1745205892, %T A265864 19070813984,210091931944,2330150737904,25993622086384, %U A265864 291414635747552,3281265369826774,37087677409301804,420618333874721044 %N A265864 Number of 3Xn arrays containing n copies of 0..3-1 with no element plus any vertical neighbor equal to 3-1. %C A265864 Row 3 of A265863. %H A265864 R. H. Hardin, <a href="/A265864/b265864.txt">Table of n, a(n) for n = 1..95</a> %e A265864 Some solutions for n=4 %e A265864 ..1..2..0..0....0..0..1..1....1..0..2..1....0..2..0..1....2..2..2..2 %e A265864 ..0..2..1..1....0..1..2..2....0..0..2..2....0..2..1..0....1..1..1..1 %e A265864 ..1..2..0..2....1..0..2..2....0..1..2..1....1..2..2..1....0..0..0..0 %Y A265864 Cf. A265863. %K A265864 nonn %O A265864 1,1 %A A265864 _R. H. Hardin_, Dec 17 2015