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A215867 Number of permutations of 0..floor((n*7-2)/2) on odd squares of an n X 7 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing. 2
1, 5, 29, 262, 1642, 15485, 97289, 918637, 5772013, 54503318, 342457898, 3233726365, 20318307913, 191859642509, 1205501906765, 11383190276278, 71523418913482, 675374034791837, 4243543228336841, 40070496565665517 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 7 of A215870.
LINKS
FORMULA
Empirical: a(n) = 61*a(n-2) -99*a(n-4) -2*a(n-6).
Empirical: g.f.: -x*(-1 -5*x +32*x^2 +43*x^3 +28*x^4 +2*x^5) / ( 1 -61*x^2 +99*x^4 +2*x^6 ). - R. J. Mathar, Nov 27 2015
EXAMPLE
Some solutions for n=4:
..x..0..x..2..x..4..x....x..0..x..2..x..4..x....x..0..x..2..x..4..x
..1..x..3..x..5..x..7....1..x..3..x..5..x..8....1..x..3..x..6..x..8
..x..6..x..9..x.10..x....x..6..x..9..x.10..x....x..5..x..7..x.10..x
..8..x.11..x.12..x.13....7..x.11..x.12..x.13....9..x.11..x.12..x.13
CROSSREFS
Sequence in context: A103815 A134752 A231712 * A342423 A342449 A345098
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 25 2012
STATUS
approved

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Last modified March 1 17:48 EST 2024. Contains 370442 sequences. (Running on oeis4.)