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 A207083 #8 Jun 18 2018 14:09:33 %S A207083 7,49,241,1117,4891,20953,88465,370753,1546879,6437929,26754673, %T A207083 111093277,461065507,1912995217,7935844129,32917778401,136534855735, %U A207083 566294540737,2348729268913,9741340873213,40401894006955,167564911503529 %N A207083 Number of n X 3 0..1 arrays avoiding 0 0 0 horizontally and 0 0 1 vertically. %C A207083 Column 3 of A207088. %H A207083 R. H. Hardin, <a href="/A207083/b207083.txt">Table of n, a(n) for n = 1..210</a> %F A207083 Empirical: a(n) = 6*a(n-1) - 5*a(n-2) - 14*a(n-3) + 11*a(n-4) + 4*a(n-5) - a(n-6). %F A207083 Empirical g.f.: x*(7 + 7*x - 18*x^2 + 14*x^3 + 3*x^4 - x^5) / ((1 - x)*(1 - 2*x - x^2)*(1 - 3*x - 5*x^2 + x^3)). - _Colin Barker_, Jun 18 2018 %e A207083 Some solutions for n=4: %e A207083 ..0..1..1....1..1..0....0..0..1....1..1..0....1..0..0....0..0..1....0..1..1 %e A207083 ..1..1..0....0..0..1....0..1..1....1..0..1....1..0..1....1..0..0....0..1..1 %e A207083 ..1..1..1....1..1..1....0..0..1....1..0..0....1..0..1....0..0..1....0..1..1 %e A207083 ..1..0..1....1..0..0....0..0..1....0..0..1....1..0..1....0..0..1....0..1..1 %Y A207083 Cf. A207088. %K A207083 nonn %O A207083 1,1 %A A207083 _R. H. Hardin_, Feb 15 2012