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A187383 Number of 9-step S, NW and NE-moving king's tours on an n X n board summed over all starting positions. 1
0, 0, 0, 340, 3060, 10320, 24892, 46412, 75567, 111492, 154187, 203652, 259887, 322892, 392667, 469212, 552527, 642612, 739467, 843092, 953487, 1070652, 1194587, 1325292, 1462767, 1607012, 1758027, 1915812, 2080367, 2251692, 2429787, 2614652 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Row 9 of A187377.

LINKS

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

FORMULA

Empirical: a(n) = 3385*n^2 - 28390*n + 56892 for n>7.

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

G.f.: x^4*(340 + 2040*x + 2160*x^2 + 2772*x^3 - 364*x^4 + 687*x^5 - 865*x^6) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>10.

(End)

CROSSREFS

Cf. A187377.

Sequence in context: A238040 A237959 A232514 * A265969 A265924 A239159

Adjacent sequences:  A187380 A187381 A187382 * A187384 A187385 A187386

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 09 2011

STATUS

approved

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Last modified December 5 12:24 EST 2021. Contains 349557 sequences. (Running on oeis4.)