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 A207698 #7 Jul 22 2025 20:41:35 %S A207698 25,625,1250,2500,10000,40000,145200,527076,2056032,8020224,29854944, %T A207698 111133764,429565416,1660399504,6232977072,23397985296,90031551120, %U A207698 346426416400,1306080208880,4924120769296,18891767424072,72479716304004 %N A207698 Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 1 vertically. %C A207698 Row 7 of A207693 %H A207698 R. H. Hardin, <a href="/A207698/b207698.txt">Table of n, a(n) for n = 1..210</a> %e A207698 Some solutions for n=4 %e A207698 ..0..0..1..1....1..1..1..0....0..0..1..1....0..0..1..1....0..1..1..0 %e A207698 ..1..1..0..1....1..0..0..1....1..1..0..0....1..1..0..1....1..0..0..1 %e A207698 ..1..1..1..0....0..1..1..1....0..0..1..1....1..1..1..0....0..1..1..0 %e A207698 ..0..0..1..1....1..1..0..0....1..1..1..1....0..0..1..1....1..0..0..1 %e A207698 ..1..1..0..0....1..0..1..1....1..1..0..0....1..1..0..1....1..1..1..0 %e A207698 ..0..1..1..1....0..1..1..0....0..0..1..1....1..1..1..0....0..1..1..1 %e A207698 ..1..0..1..1....1..1..0..1....1..0..1..1....0..0..1..1....1..0..0..1 %K A207698 nonn %O A207698 1,1 %A A207698 _R. H. Hardin_ Feb 19 2012