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 A223744 #9 Jul 23 2025 04:27:07 %S A223744 9,9,81,81,1521,1849,38025,59049,1461681,2368521,64112049,111450249, %T A223744 3167100729,5714604025,167633743761,311494585689,9370449532161, %U A223744 17792173577929,545559866271729,1054096283988801,32828183598395025 %N A223744 Number of nX3 0..2 arrays with every row and column least squares fitting to a zero slope straight line, with a single point array taken as having zero slope. %C A223744 Column 3 of A223747 %H A223744 R. H. Hardin, <a href="/A223744/b223744.txt">Table of n, a(n) for n = 1..33</a> %e A223744 Some solutions for n=6 %e A223744 ..1..2..1....2..2..2....1..2..1....1..2..1....1..1..1....2..1..2....0..2..0 %e A223744 ..0..2..0....2..1..2....1..0..1....1..0..1....1..1..1....0..2..0....2..2..2 %e A223744 ..1..1..1....0..0..0....2..0..2....1..1..1....1..2..1....0..0..0....0..2..0 %e A223744 ..1..1..1....0..2..0....0..0..0....1..1..1....1..0..1....0..0..0....0..2..0 %e A223744 ..0..2..0....2..2..2....0..0..0....1..0..1....1..0..1....0..2..0....2..2..2 %e A223744 ..1..2..1....2..1..2....2..2..2....1..2..1....1..2..1....2..1..2....0..2..0 %K A223744 nonn %O A223744 1,1 %A A223744 _R. H. Hardin_ Mar 27 2013