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 A187524 #6 Jan 01 2024 19:02:36 %S A187524 0,1780,73764,1655170,8174314,70304076,193687886 %N A187524 Number of 5 X 5 0..n arrays with the array of 2 X 2 subblock determinants antisymmetric and no off-diagonal 2 X 2 subblock determinant zero. %C A187524 Row 4 of A187521. %e A187524 Some solutions for 5 X 5 %e A187524 ..1..2..2..2..2....0..0..2..1..2....2..2..1..0..1....0..0..3..0..2 %e A187524 ..1..2..1..2..1....2..2..2..3..0....1..1..1..2..3....2..1..1..2..0 %e A187524 ..0..2..1..1..0....0..2..2..1..2....2..1..1..1..2....3..3..3..3..1 %e A187524 ..1..1..1..1..1....2..0..2..1..1....2..0..1..1..1....2..0..1..1..0 %e A187524 ..0..2..3..2..2....2..3..3..2..2....2..1..2..3..3....3..2..1..2..0 %Y A187524 Cf. A187521. %K A187524 nonn %O A187524 1,2 %A A187524 _R. H. Hardin_, Mar 10 2011