OFFSET
1,2
COMMENTS
Row 8 of A187162.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..50
FORMULA
Empirical: a(n) = 81390*n^3 - 463074*n^2 + 801216*n - 418032 for n>6.
Conjectures from Colin Barker, Apr 21 2018: (Start)
G.f.: 12*x^2*(12 + 5604*x + 28208*x^2 + 13272*x^3 - 6080*x^4 - 1320*x^5 + 748*x^6 + 233*x^7 + 18*x^8) / (1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>10.
(End)
EXAMPLE
A solution for 3 X 3 X 3:
..0..8..0.....2..7..0.....3..0..0
..0..0..0.....1..6..0.....4..5..0
..0..0..0.....0..0..0.....0..0..0
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
R. H. Hardin, Mar 06 2011
STATUS
approved