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A209548
1/4 the number of (n+1)X4 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences
1
61, 562, 5075, 46515, 425803, 3901194, 35741496, 327471411, 3000373035, 27490276714, 251873944521, 2307743577771, 21144231048767, 193729722925588, 1775009260945536, 16263162106133544, 149007922275551448
OFFSET
1,1
COMMENTS
Column 3 of A209553
LINKS
FORMULA
Empirical: a(n) = 15*a(n-1) -59*a(n-2) +27*a(n-3) +267*a(n-4) -488*a(n-5) +111*a(n-6) +312*a(n-7) -174*a(n-8) -30*a(n-9) +18*a(n-10) +2*a(n-11)
EXAMPLE
Some solutions for n=4
..1..0..3..0....1..0..3..0....1..2..1..2....3..2..3..0....3..1..3..1
..0..1..2..1....2..3..0..3....0..3..2..3....2..3..2..1....1..3..1..3
..3..2..1..2....1..2..1..2....3..0..1..0....1..0..1..2....3..1..3..1
..0..1..0..3....2..1..0..3....2..1..2..1....0..1..2..1....1..3..1..3
..1..0..1..2....1..2..3..0....3..0..1..0....3..2..3..2....3..1..3..1
CROSSREFS
Sequence in context: A302531 A061002 A303412 * A302898 A234926 A355602
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 10 2012
STATUS
approved