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A187588
Number of 5-step E, S, NW and NE-moving king's tours on an n X n board summed over all starting positions.
1
0, 0, 106, 578, 1484, 2794, 4508, 6626, 9148, 12074, 15404, 19138, 23276, 27818, 32764, 38114, 43868, 50026, 56588, 63554, 70924, 78698, 86876, 95458, 104444, 113834, 123628, 133826, 144428, 155434, 166844, 178658, 190876, 203498, 216524
OFFSET
1,3
COMMENTS
Row 5 of A187586.
LINKS
FORMULA
Empirical: a(n) = 202*n^2 - 912*n + 994 for n>3.
Empirical G.f.: 2*x^3*(53+130*x+34*x^2-15*x^3)/(1-x)^3. [Colin Barker, Jan 22 2012]
EXAMPLE
Some solutions for 4 X 4
..0..5..0..0....0..5..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..4..0....0..3..4..0....0..0..4..5....0..0..0..0....0..0..2..0
..0..0..1..3....0..1..2..0....0..0..2..3....0..0..2..4....0..1..3..5
..0..0..2..0....0..0..0..0....0..0..0..1....0..1..3..5....0..0..4..0
CROSSREFS
Cf. A187586.
Sequence in context: A234421 A234414 A090037 * A051974 A188837 A184217
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 11 2011
STATUS
approved