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 A262850 #4 Oct 03 2015 16:12:03 %S A262850 6,6,12,318,900,4536,34782,178926,1042284,6538206,38160540,227814120, %T A262850 1377960126,8227422006,49321272972,296370593598,1776644188020, %U A262850 10658199015576,63967089528222,383739633130686,2302372435469484 %N A262850 Number of (1+2)X(n+2) 0..1 arrays with each row divisible by 7 and column not divisible by 7, read as a binary number with top and left being the most significant bits. %C A262850 Row 1 of A262849. %H A262850 R. H. Hardin, <a href="/A262850/b262850.txt">Table of n, a(n) for n = 1..210</a> %F A262850 Empirical: a(n) = 6*a(n-1) +72*a(n-3) -432*a(n-4) -1270*a(n-6) +7620*a(n-7) -2880*a(n-9) +17280*a(n-10) +113591*a(n-12) -681546*a(n-13) +115128*a(n-15) -690768*a(n-16) %e A262850 Some solutions for n=4 %e A262850 ..1..0..1..0..1..0....1..1..1..0..0..0....1..0..1..0..1..0....0..1..0..1..0..1 %e A262850 ..0..0..0..0..0..0....0..0..0..0..0..0....0..1..0..1..0..1....0..0..0..0..0..0 %e A262850 ..1..1..1..1..1..1....0..0..0..1..1..1....0..1..1..1..0..0....1..1..1..1..1..1 %Y A262850 Cf. A262849. %K A262850 nonn %O A262850 1,1 %A A262850 _R. H. Hardin_, Oct 03 2015