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A215787
Number of permutations of 0..floor((n*9-1)/2) on even squares of an nX9 array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing
1
1, 14, 462, 11694, 530429, 14296434, 673507749, 18255280444, 862827082115, 23397688110992, 1106178923600669, 29997930933948284, 1418251919293188195, 38461009542931961924, 1818375422885354065137, 49311812528326463481148
OFFSET
1,2
COMMENTS
Column 9 of A215788
LINKS
FORMULA
Empirical: a(n) = 1385*a(n-2) -131648*a(n-4) -318070*a(n-6) -4160916*a(n-8) -1097892*a(n-10) +648*a(n-12)
EXAMPLE
Some solutions for n=4
..0..x..1..x..3..x..6..x..8....0..x..1..x..2..x..6..x.11
..x..2..x..5..x.10..x.13..x....x..3..x..5..x..8..x.12..x
..4..x..7..x.11..x.14..x.15....4..x..7..x.10..x.14..x.16
..x..9..x.12..x.16..x.17..x....x..9..x.13..x.15..x.17..x
CROSSREFS
Sequence in context: A282245 A319096 A297548 * A005790 A208563 A200061
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 23 2012
STATUS
approved