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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.

A187708 Number of 5X5 0..n arrays with each 2X2 subblock off diagonal and antidiagonal nonsingular and the array of 2X2 subblock determinants antisymmetric about the diagonal and antidiagonal.

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%I A187708 #6 Jul 22 2025 10:53:51
%S A187708 34,5030,81456,875696,4225652,22532156,67940472,225606354,577091334,
%T A187708 1469652502
%N A187708 Number of 5X5 0..n arrays with each 2X2 subblock off diagonal and antidiagonal nonsingular and the array of 2X2 subblock determinants antisymmetric about the diagonal and antidiagonal.
%C A187708 Row 4 of A187705
%e A187708 Some n=3 solutions for 5X5
%e A187708 ..0..1..1..1..2....2..2..1..2..2....2..2..1..2..2....0..0..1..0..0
%e A187708 ..0..1..2..1..2....1..1..0..2..2....1..1..2..1..1....1..3..0..3..3
%e A187708 ..1..0..0..0..1....1..2..0..1..0....3..0..0..0..3....0..3..0..3..2
%e A187708 ..1..1..1..1..0....2..2..0..1..1....1..1..2..1..0....1..3..0..3..3
%e A187708 ..2..2..1..2..0....0..0..1..3..3....3..3..3..3..0....0..0..1..2..2
%K A187708 nonn
%O A187708 1,1
%A A187708 _R. H. Hardin_ Mar 12 2011

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