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A187192

Number of 5-turn rook's tours on an n X n board summed over all starting positions.

0, 0, 720, 9792, 58800, 231840, 705600, 1800960, 4046112, 8251200, 15594480, 27720000, 46846800, 75889632, 118591200, 179665920, 264955200, 381594240, 538190352

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

OFFSET

1,3

LINKS

Table of n, a(n) for n=1..19.

FORMULA

Empirical: a(n) = 16*n^6 - 98*n^5 + 228*n^4 - 238*n^3 + 92*n^2.

Empirical G.f.: 48*x^3*(15+99*x+112*x^2+14*x^3)/(1-x)^7. [Colin Barker, Jan 22 2012]

EXAMPLE

Some solutions for 3X3

..0..5..1....0..0..4....0..1..5....1..0..2....1..0..0....4..0..5....2..3..1

..0..0..2....2..0..3....0..3..4....0..5..0....2..0..5....3..0..0....0..0..0

..0..4..3....1..0..5....0..2..0....0..4..3....3..0..4....2..1..0....5..4..0

CROSSREFS

Row 5 of A187189.

Sequence in context: A119540 A052784 A052786 * A052792 A052790 A052521

Adjacent sequences: A187189 A187190 A187191 * A187193 A187194 A187195

KEYWORD

nonn,more

AUTHOR

R. H. Hardin, Mar 06 2011

STATUS

approved

URL: https://oeis.org/A187192

⇱ A187192 - OEIS