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 A206999 #7 Jul 22 2025 19:55:09 %S A206999 65,4225,105936,2346621,41429335,683241763,10432265840,154004233160, %T A206999 2204564726744,31044446020755,431344655622502,5945601513772082, %U A206999 81452204001027552,1111514446777014206,15124130993994618127 %N A206999 Number of nX7 0..1 arrays avoiding 0 1 0 horizontally and 0 1 1 vertically. %C A206999 Column 7 of A207000 %H A206999 R. H. Hardin, <a href="/A206999/b206999.txt">Table of n, a(n) for n = 1..210</a> %e A206999 Some solutions for n=4 %e A206999 ..0..0..0..1..1..0..1....1..0..1..1..0..0..0....1..0..1..1..1..0..0 %e A206999 ..1..0..0..1..1..1..1....1..1..1..0..0..0..0....0..1..1..1..1..0..0 %e A206999 ..0..0..1..1..1..0..0....1..0..0..0..1..1..1....0..0..1..1..0..1..1 %e A206999 ..1..1..0..1..1..1..1....0..0..1..1..0..0..0....0..0..1..1..1..0..0 %K A206999 nonn %O A206999 1,1 %A A206999 _R. H. Hardin_ Feb 14 2012