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 A263369 #4 Oct 16 2015 07:31:30 %S A263369 5,29,865,24711,826249,27274339,943196037,32850517101,1149496602927, %T A263369 40220123519645,1407588920518393,49261304582570101, %U A263369 1724108144663303417,60343312266592642007,2112014898505756338577,73920482899832743087347 %N A263369 Number of (n+1)X(4+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 A263369 Column 4 of A263373. %H A263369 R. H. Hardin, <a href="/A263369/b263369.txt">Table of n, a(n) for n = 1..210</a> %e A263369 Some solutions for n=4 %e A263369 ..0..0..2..1..0....1..0..1..0..1....0..1..0..2..2....1..1..0..1..1 %e A263369 ..1..2..0..1..2....1..1..2..0..0....1..1..2..0..0....0..0..0..0..0 %e A263369 ..0..1..0..0..1....2..0..2..0..2....0..0..0..2..1....0..1..0..0..1 %e A263369 ..0..0..2..1..0....0..2..0..0..2....0..1..0..0..1....1..2..0..1..2 %e A263369 ..1..0..0..1..0....0..2..1..0..0....1..1..2..2..1....0..2..0..0..2 %Y A263369 Cf. A263373. %K A263369 nonn %O A263369 1,1 %A A263369 _R. H. Hardin_, Oct 16 2015