A130666 Number of ways of placing non-attacking knights on an n X n chessboard symmetric about both diagonal and antidiagonal.

1, 2, 4, 10, 21, 89, 248, 1652, 5760, 59789, 268529, 4367552, 24922412, 641484896, 4607113999, 188770443286, 1702258930069, 111575238563044, 1256539208451845, 132483845142611245, 1854392449274745630, 316017552098202250347

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Crossrefs

Sequence in context: A301700 A123445 A104431 * A179116 A358357 A036954

Adjacent sequences: A130663 A130664 A130665 * A130667 A130668 A130669

Keyword

nonn

Author

R. H. Hardin, Aug 25 2008

Status

approved