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A187587 Number of 4-step E, S, NW and NE-moving king's tours on an n X n board summed over all starting positions 1
0, 5, 84, 286, 604, 1038, 1588, 2254, 3036, 3934, 4948, 6078, 7324, 8686, 10164, 11758, 13468, 15294, 17236, 19294, 21468, 23758, 26164, 28686, 31324, 34078, 36948, 39934, 43036, 46254, 49588, 53038, 56604, 60286, 64084, 67998, 72028, 76174, 80436, 84814 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 4 of A187586

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..50

FORMULA

Empirical: a(n) = 58*n^2 - 204*n + 174 for n>2.

Empirical G.f.: x^2*(5+69*x+49*x^2-7*x^3)/(1-x)^3. [Colin Barker, Jan 22 2012]

EXAMPLE

Some solutions for 4X4

..0..0..0..0....0..0..0..0....0..2..0..0....0..0..0..0....0..0..2..4

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

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

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

CROSSREFS

Sequence in context: A216146 A111834 A271219 * A006471 A258391 A061628

Adjacent sequences:  A187584 A187585 A187586 * A187588 A187589 A187590

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 11 2011

STATUS

approved

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Last modified December 17 04:09 EST 2017. Contains 296096 sequences.