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A215295 Number of permutations of 0..floor((n*5-2)/2) on odd squares of an nX5 array such that each row and column of odd squares is increasing 1
1, 10, 70, 2100, 23100, 1051050, 14294280, 814773960, 12547518984, 824551247520, 13781785137120, 999179422441200, 17699749768958400, 1379105502831342000, 25513451802379827000, 2100607531729272423000, 40191624107086745693400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 5 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(2,f3)*A060854(3,f4)*binomial(2*f3+3*f4,2*f3)

EXAMPLE

Some solutions for n=5

..x..2..x..6..x....x..1..x..5..x....x..0..x..5..x....x..0..x..2..x

..0..x..3..x..4....0..x..2..x..7....2..x..4..x.10....3..x..6..x..8

..x..5..x.10..x....x..3..x..9..x....x..1..x..8..x....x..1..x..7..x

..1..x..7..x..8....4..x..6..x.11....6..x..7..x.11....4..x..9..x.11

..x..9..x.11..x....x..8..x.10..x....x..3..x..9..x....x..5..x.10..x

CROSSREFS

Sequence in context: A038779 A246427 A172499 * A136856 A016218 A026772

Adjacent sequences:  A215292 A215293 A215294 * A215296 A215297 A215298

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 07 2012

STATUS

approved

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Last modified February 19 16:02 EST 2019. Contains 320311 sequences. (Running on oeis4.)