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A187157 Number of 4-step one space at a time bishop's tours on an n X n board summed over all starting positions. 1
0, 0, 8, 92, 248, 476, 776, 1148, 1592, 2108, 2696, 3356, 4088, 4892, 5768, 6716, 7736, 8828, 9992, 11228, 12536, 13916, 15368, 16892, 18488, 20156, 21896, 23708, 25592, 27548, 29576, 31676, 33848, 36092, 38408, 40796, 43256, 45788, 48392, 51068, 53816 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Row 4 of A187155.

LINKS

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

FORMULA

Empirical: a(n) = 36*n^2 - 168*n + 188 for n>2.

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

G.f.: 4*x^3*(2 + 17*x - x^2) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>5.

(End)

EXAMPLE

Some solutions for 4 X 4:

..0..0..4..0....0..0..0..0....0..0..0..0....0..0..4..0....0..4..0..0

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

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

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

CROSSREFS

Cf. A187155.

Sequence in context: A302614 A220573 A303743 * A215057 A222400 A280159

Adjacent sequences:  A187154 A187155 A187156 * A187158 A187159 A187160

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 06 2011

STATUS

approved

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Last modified July 18 12:26 EDT 2018. Contains 312739 sequences. (Running on oeis4.)