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A215296 Number of permutations of 0..floor((n*7-2)/2) on odd squares of an nX7 array such that each row and column of odd squares is increasing 1
1, 35, 1050, 210210, 14294280, 5703417720, 577185873264, 337653735859440, 43364386933948080, 32436561426593163840, 4886336289191784467040, 4340695403565368534887200, 733267473530864041786302000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 7 of A215297

LINKS

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

FORMULA

f3=floor((n+1)/2)

f4=floor(n/2)

a(n) = A060854(3,f3)*A060854(4,f4)*binomial(3*f3+4*f4,3*f3)

EXAMPLE

Some solutions for n=3

..x..0..x..1..x..3..x....x..0..x..2..x..5..x....x..0..x..1..x..3..x

..2..x..4..x..6..x..9....3..x..6..x..8..x..9....5..x..6..x..8..x..9

..x..5..x..7..x..8..x....x..1..x..4..x..7..x....x..2..x..4..x..7..x

CROSSREFS

Sequence in context: A210313 A049395 A278723 * A209180 A115492 A187538

Adjacent sequences:  A215293 A215294 A215295 * A215297 A215298 A215299

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 07 2012

STATUS

approved

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Last modified June 25 12:55 EDT 2019. Contains 324352 sequences. (Running on oeis4.)