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A187160 Number of 7-step one space at a time bishop's tours on an n X n board summed over all starting positions. 1
0, 0, 0, 16, 544, 2328, 6172, 11576, 18540, 27064, 37148, 48792, 61996, 76760, 93084, 110968, 130412, 151416, 173980, 198104, 223788, 251032, 279836, 310200, 342124, 375608, 410652, 447256, 485420, 525144, 566428, 609272, 653676, 699640, 747164 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Row 7 of A187155.

LINKS

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

FORMULA

Empirical: a(n) = 780*n^2 - 6296*n + 12024 for n>5.

Conjectures from Colin Barker, Apr 20 2018: (Start)

G.f.: 4*x^4*(4 + 124*x + 186*x^2 + 201*x^3 - 125*x^4) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>8.

(End)

EXAMPLE

Some solutions for 4 X 4:

..0..0..4..0....0..7..0..1....7..0..5..0....0..2..0..0....0..0..6..0

..0..3..0..5....6..0..2..0....0..6..0..4....1..0..3..0....0..5..0..7

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

..0..1..0..7....0..0..4..0....0..2..0..0....7..0..5..0....0..3..0..1

CROSSREFS

Cf. A187155.

Sequence in context: A220729 A196298 A274136 * A196216 A196683 A131515

Adjacent sequences:  A187157 A187158 A187159 * A187161 A187162 A187163

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 06 2011

STATUS

approved

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Last modified September 18 00:01 EDT 2021. Contains 347489 sequences. (Running on oeis4.)