

A187050


Number of 6step one or two space at a time bishop's tours on an n X n board summed over all starting positions.


1



0, 0, 0, 584, 6952, 29500, 79088, 162320, 281320, 435436, 623508, 845084, 1100164, 1388748, 1710836, 2066428, 2455524, 2878124, 3334228, 3823836, 4346948, 4903564, 5493684, 6117308, 6774436, 7465068, 8189204, 8946844, 9737988, 10562636
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OFFSET

1,4


COMMENTS



LINKS



FORMULA

Empirical: a(n) = 16752*n^2  163720*n + 397436 for n>9.
G.f.: 4*x^3*(146 + 1300*x + 2599*x^2 + 2715*x^3 + 1651*x^4 + 531*x^5  163*x^6  290*x^7  113*x^8) / (1  x)^3.
a(n) = 3*a(n1)  3*a(n2) + a(n3) for n>12.
(End)


EXAMPLE

Some solutions for 4 X 4:
..0..0..0..0....0..4..0..0....3..0..5..0....3..0..1..0....0..0..4..0
..0..5..0..3....5..0..3..0....0..4..0..1....0..2..0..5....0..5..0..1
..1..0..4..0....0..6..0..2....6..0..2..0....0..0..4..0....3..0..6..0
..0..2..0..6....0..0..1..0....0..0..0..0....0..6..0..0....0..2..0..0


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



