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A204707
Number of (n+1) X 3 0..1 arrays with the permanents of all 2 X 2 subblocks equal and nonzero.
1
13, 33, 81, 209, 529, 1361, 3473, 8913, 22801, 58449, 149649, 383441, 982033, 2515793, 6443921, 16507089, 42282769, 108311121, 277442193, 710686673, 1820455441, 4663202129, 11945023889, 30597832401, 78377927953, 200769257553
OFFSET
1,1
COMMENTS
Column 2 of A204713.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +3*a(n-2) -4*a(n-3).
Conjectures from Colin Barker, Jun 09 2018: (Start)
G.f.: x*(13 + 7*x - 24*x^2) / ((1 - x)*(1 - x - 4*x^2)).
a(n) = 1 + (2^(-1-n)*((1-sqrt(17))^n*(-19+5*sqrt(17)) + (1+sqrt(17))^n*(19+5*sqrt(17)))) / sqrt(17).
(End)
EXAMPLE
Some solutions for n=4:
..1..0..1....0..1..0....1..1..1....0..1..1....1..1..0....0..1..1....0..1..1
..1..1..1....1..1..1....0..1..0....1..0..1....0..1..1....1..1..0....1..0..1
..1..0..1....1..0..1....1..1..1....1..1..0....1..0..1....0..1..1....1..1..1
..1..1..1....0..1..0....1..0..1....0..1..1....1..1..0....1..1..0....1..0..1
..1..0..1....1..1..1....0..1..1....1..1..0....0..1..1....1..0..1....0..1..1
CROSSREFS
Cf. A204713.
Sequence in context: A024839 A146177 A146194 * A282686 A124659 A164539
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 18 2012
STATUS
approved