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 A187635 #6 Jul 22 2025 10:51:33 %S A187635 954,557382,31903442,686589106,7836968262 %N A187635 Number of 5X5 0..n arrays with the array of 2X2 subblock determinants antisymmetric under horizontal and vertical reflection and each non-centerline 2X2 subblock nonsingular. %C A187635 Row 4 of A187633 %e A187635 Some n=3 solutions for 5X5 %e A187635 ..2..0..2..1..2....2..0..2..1..2....2..0..2..3..2....2..0..2..0..2 %e A187635 ..0..1..0..1..0....0..3..0..3..0....0..2..0..2..0....0..2..2..2..2 %e A187635 ..1..2..3..1..1....3..0..2..0..3....2..2..1..1..2....3..0..1..0..3 %e A187635 ..0..1..0..1..0....0..3..1..3..1....0..2..0..2..0....0..2..0..2..2 %e A187635 ..2..1..2..0..2....2..3..3..3..3....2..0..2..3..2....2..0..2..1..3 %K A187635 nonn %O A187635 1,1 %A A187635 _R. H. Hardin_ Mar 12 2011