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 A207784 #7 Jul 22 2025 20:50:34 %S A207784 25,625,2815,12567,46199,185613,786907,3121285,12547290,51431686, %T A207784 207462822,837211531,3399092159,13752531706,55605190507,225211225477, %U A207784 911554639912,3688266309172,14929725196351,60428546476595 %N A207784 Number of nX7 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 0 1 vertically. %C A207784 Column 7 of A207785 %H A207784 R. H. Hardin, <a href="/A207784/b207784.txt">Table of n, a(n) for n = 1..210</a> %e A207784 Some solutions for n=4 %e A207784 ..1..1..0..1..0..1..0....1..1..0..0..1..0..1....0..1..0..1..0..1..0 %e A207784 ..1..1..1..1..0..0..1....0..1..0..1..0..1..0....1..1..0..1..0..1..0 %e A207784 ..1..0..1..0..1..0..0....0..0..1..0..0..1..0....1..1..1..1..1..1..1 %e A207784 ..1..0..1..0..0..1..0....1..0..1..0..1..0..1....1..1..0..0..1..0..0 %K A207784 nonn %O A207784 1,1 %A A207784 _R. H. Hardin_ Feb 20 2012