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 A262916 #3 Oct 04 2015 10:12:53 %S A262916 1,86,783,17333,1444558,30497815,1282949605,102437680622 %N A262916 Number of (n+1)X(7+1) 0..1 arrays with each row divisible by 3 and each column divisible by 7, read as a binary number with top and left being the most significant bits. %C A262916 Column 7 of A262917. %e A262916 Some solutions for n=4 %e A262916 ..1..1..0..1..1..0..0..0....0..1..0..0..0..1..0..1....1..0..0..0..0..1..0..0 %e A262916 ..0..1..0..1..0..0..0..1....0..0..0..0..0..0..1..1....0..0..0..1..0..0..1..0 %e A262916 ..1..1..1..1..1..0..0..1....1..1..1..1..1..1..1..1....1..1..1..1..0..1..1..0 %e A262916 ..0..0..1..0..0..0..0..1....1..0..1..1..1..0..1..0....0..1..1..1..0..0..1..0 %e A262916 ..1..0..1..0..1..0..0..0....1..1..1..1..1..1..0..0....1..1..1..0..0..1..0..0 %Y A262916 Cf. A262917. %K A262916 nonn %O A262916 1,2 %A A262916 _R. H. Hardin_, Oct 04 2015