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A209725
1/4 the number of (n+1) X 7 0..2 arrays with every 2 X 2 subblock having distinct clockwise edge differences.
1
12, 13, 14, 16, 18, 22, 26, 34, 42, 58, 74, 106, 138, 202, 266, 394, 522, 778, 1034, 1546, 2058, 3082, 4106, 6154, 8202, 12298, 16394, 24586, 32778, 49162, 65546, 98314, 131082, 196618, 262154, 393226, 524298, 786442, 1048586, 1572874, 2097162
OFFSET
1,1
COMMENTS
Column 6 of A209727.
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3).
Conjectures from Colin Barker, Jul 12 2018: (Start)
G.f.: x*(12 + x - 23*x^2) / ((1 - x)*(1 - 2*x^2)).
a(n) = 3*2^(n/2 - 1) + 10 for n even.
a(n) = 2^((n + 1)/2) + 10 for n odd.
(End)
EXAMPLE
Some solutions for n=4:
..1..0..1..0..1..0..1....2..0..2..0..1..0..2....0..1..0..1..0..1..0
..0..2..0..2..0..2..0....1..2..1..2..0..2..1....2..0..2..0..2..0..2
..1..0..1..0..1..0..1....2..0..2..0..1..0..2....0..1..0..1..0..1..0
..0..2..0..2..0..2..0....1..2..1..2..0..2..1....2..0..2..0..2..0..2
..1..0..1..0..1..0..1....2..0..2..0..1..0..2....0..1..0..1..0..1..0
CROSSREFS
Cf. A209727.
Sequence in context: A270041 A272270 A133894 * A045879 A257073 A239722
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 12 2012
STATUS
approved