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 A267728 #6 Apr 20 2020 19:46:33 %S A267728 2,16,512,39330,9116396,4977655636,6910434801148,22619851307136958, %T A267728 176312563812861434000 %N A267728 Number of n X n 0..1 arrays with every repeated value in every row and column greater than or equal to the previous repeated value. %C A267728 Diagonal of A267735. %e A267728 Some solutions for n=4 %e A267728 ..1..0..1..0....1..1..0..1....1..0..0..1....0..0..0..0....0..1..1..0 %e A267728 ..0..1..0..0....0..1..1..1....0..0..1..0....0..0..0..0....0..1..1..1 %e A267728 ..0..0..1..1....1..1..1..1....0..0..1..0....0..0..1..1....1..1..1..0 %e A267728 ..0..0..0..0....0..1..0..0....1..1..1..1....1..0..1..0....1..0..1..0 %Y A267728 Cf. A267735. %K A267728 nonn %O A267728 1,1 %A A267728 _R. H. Hardin_, Jan 20 2016