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A186863 Number of 4-step king's tours on an n X n board summed over all starting positions 0
0, 24, 496, 1764, 3768, 6508, 9984, 14196, 19144, 24828, 31248, 38404, 46296, 54924, 64288, 74388, 85224, 96796, 109104, 122148, 135928, 150444, 165696, 181684, 198408, 215868, 234064, 252996, 272664, 293068, 314208, 336084, 358696 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 4 of A186861

LINKS

Table of n, a(n) for n=1..33.

FORMULA

Empirical: a(n) = 368*n^2 - 1308*n + 1108 for n>2.

Empirical G.f.: 4*x^2*(6+106*x+87*x^2-15*x^3)/(1-x)^3. [Colin Barker, Jan 22 2012]

EXAMPLE

Some solutions for 3X3

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

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

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

CROSSREFS

Sequence in context: A275041 A109143 A260964 * A004383 A112390 A166757

Adjacent sequences:  A186860 A186861 A186862 * A186864 A186865 A186866

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 27 2011

STATUS

approved

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Last modified June 20 09:27 EDT 2019. Contains 324234 sequences. (Running on oeis4.)