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A233166 Number of n X 6 0..7 arrays with no element x(i,j) adjacent to itself or value 7-x(i,j) horizontally, diagonally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 3 4 5 and 6, 2 appearing before 3 4 and 5, and 3 appearing before 4 in row major order (unlabelled 8-colorings with no clashing color pairs). 1
236, 4096, 278528, 19922944, 1543503872, 133143986176, 12919261626368, 1389782697508864, 161003686678495232, 19527607984278470656, 2430358531711233425408, 306658673481347586064384 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 192*a(n-1) - 8192*a(n-2) for n>3.
Conjectures from Colin Barker, Oct 09 2018: (Start)
G.f.: 4*x*(59 - 10304*x + 356352*x^2) / ((1 - 64*x)*(1 - 128*x)).
a(n) = 64^(n-1) * (2^n+60) for n>1.
(End)
EXAMPLE
Some solutions for n=2:
..0..1..0..6..7..2....0..1..2..6..7..3....0..1..2..6..0..1....0..1..2..3..0..6
..3..5..4..2..4..6....2..4..7..4..2..1....5..3..0..4..2..4....2..3..0..1..2..4
CROSSREFS
Column 6 of A233168.
Sequence in context: A251491 A251484 A247475 * A138820 A218649 A285156
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 05 2013
STATUS
approved

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Last modified February 26 07:39 EST 2024. Contains 370335 sequences. (Running on oeis4.)