A232647 Number of (n+2) X (n+2) 0..1 arrays x(i,j) with Sum_{j=1..n+2} j*x(i,j) equal for every row, Sum{i=1..n+2} i*x(i,j) equal for every column, and upper left element zero.

2, 2, 7, 7, 186, 2004, 27453, 419803

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for n=5:
..0..1..0..0..1..0..1....0..0..1..0..1..1..0....0..1..0..0..1..0..1
..0..1..0..0..1..0..1....0..1..0..0..1..0..1....1..1..0..0..1..1..0
..1..0..1..1..0..1..0....1..0..1..1..0..1..0....1..0..1..1..0..1..0
..1..0..0..0..0..1..1....0..0..1..0..1..1..0....1..1..0..0..1..1..0
..0..1..1..1..1..0..0....1..1..0..1..0..0..1....1..0..1..1..0..1..0
..0..1..1..1..1..0..0....1..0..1..1..0..1..0....0..0..1..1..0..0..1
..1..0..0..0..0..1..1....0..1..0..0..1..0..1....0..1..0..0..1..0..1

Crossrefs

Diagonal of A232654.

Sequence in context: A195326 A263868 A263793 * A379390 A091665 A019905

Adjacent sequences: A232644 A232645 A232646 * A232648 A232649 A232650

Keyword

nonn,more

Author

R. H. Hardin, Nov 27 2013

Status

approved