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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 9 of A215788

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences:  A215784 A215785 A215786 * A215788 A215789 A215790

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 23 2012

STATUS

approved

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Last modified August 7 15:08 EDT 2020. Contains 336276 sequences. (Running on oeis4.)