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A187511 Number of 6-step S, E, and NW-moving king's tours on an n X n board summed over all starting positions. 1
0, 0, 36, 272, 772, 1525, 2524, 3769, 5260, 6997, 8980, 11209, 13684, 16405, 19372, 22585, 26044, 29749, 33700, 37897, 42340, 47029, 51964, 57145, 62572, 68245, 74164, 80329, 86740, 93397, 100300, 107449, 114844, 122485, 130372, 138505, 146884 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Row 6 of A187507.

LINKS

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

FORMULA

Empirical: a(n) = 123*n^2 - 600*n + 697 for n>4.

Conjectures from Colin Barker, Apr 24 2018: (Start)

G.f.: x^3*(36 + 164*x + 64*x^2 - 11*x^3 - 7*x^4) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>7.

(End)

EXAMPLE

Some solutions for 4 X 4:

..0..0..0..0....1..2..0..0....0..0..2..0....0..0..6..0....0..0..6..0

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

..6..4..2..0....6..4..0..0....0..0..4..5....0..0..2..3....0..1..2..3

..0..0..0..1....0..5..0..0....0..0..0..6....0..0..0..1....0..0..0..0

CROSSREFS

Cf. A187507.

Sequence in context: A135181 A220159 A202958 * A185243 A014136 A245435

Adjacent sequences:  A187508 A187509 A187510 * A187512 A187513 A187514

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 10 2011

STATUS

approved

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Last modified June 16 14:16 EDT 2021. Contains 345057 sequences. (Running on oeis4.)