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 A263371 #4 Oct 16 2015 07:33:06 %S A263371 19,367,107514,27274339,8491666657,2535097569590,787253224440475, %T A263371 245171742019939573,76738178529099193548,24012353212352081646593, %U A263371 7515855702189389861141905,2352317017039363043975969464 %N A263371 Number of (n+1)X(6+1) 0..2 arrays with each row and column divisible by 7, read as a base-3 number with top and left being the most significant digits. %C A263371 Column 6 of A263373. %H A263371 R. H. Hardin, <a href="/A263371/b263371.txt">Table of n, a(n) for n = 1..188</a> %e A263371 Some solutions for n=3 %e A263371 ..1..0..0..0..2..0..2....0..0..1..1..1..0..2....0..0..0..2..1..2..1 %e A263371 ..0..0..1..2..0..1..2....1..0..0..1..2..1..0....0..0..1..1..0..1..1 %e A263371 ..0..0..1..1..0..1..1....1..2..0..2..1..1..0....0..2..1..2..0..0..2 %e A263371 ..1..0..2..0..2..2..2....2..1..1..0..1..2..2....0..1..2..1..1..0..0 %Y A263371 Cf. A263373. %K A263371 nonn %O A263371 1,1 %A A263371 _R. H. Hardin_, Oct 16 2015