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A186862 Number of 3-step king's tours on an n X n board summed over all starting positions 0
0, 24, 160, 408, 768, 1240, 1824, 2520, 3328, 4248, 5280, 6424, 7680, 9048, 10528, 12120, 13824, 15640, 17568, 19608, 21760, 24024, 26400, 28888, 31488, 34200, 37024, 39960 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 3 of A186861

LINKS

Table of n, a(n) for n=1..28.

FORMULA

Empirical: a(n) = 56*n^2 - 144*n + 88.

Empirical G.f.: 8*x^2*(3+11*x)/(1-x)^3. [Colin Barker, Jan 22 2012]

EXAMPLE

Some solutions for 3X3

..0..0..0....0..1..0....2..1..0....0..1..0....0..0..0....0..0..0....0..1..0

..3..0..0....2..3..0....3..0..0....0..2..3....0..1..0....0..0..0....2..0..0

..2..1..0....0..0..0....0..0..0....0..0..0....3..2..0....1..2..3....3..0..0

CROSSREFS

Sequence in context: A222002 A240268 A231341 * A305165 A294110 A136380

Adjacent sequences:  A186859 A186860 A186861 * A186863 A186864 A186865

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 27 2011

STATUS

approved

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Last modified June 20 05:01 EDT 2019. Contains 324229 sequences. (Running on oeis4.)