A187383 Number of 9-step S, NW and NE-moving king's tours on an n X n board summed over all starting positions.

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

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