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A218759
Unmatched value maps: number of n X 2 binary arrays indicating the locations of corresponding elements not equal to any horizontal or vertical neighbor in a random 0..1 n X 2 array.
2
2, 6, 18, 47, 134, 373, 1035, 2889, 8050, 22420, 62477, 174072, 484983, 1351277, 3764915, 10489750, 29226504, 81430659, 226881448, 632135485, 1761251171, 4907184849, 13672362150, 38093833868, 106136756981, 295717444696
OFFSET
1,1
COMMENTS
Column 2 of A218765.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) + 3*a(n-3) + 2*a(n-5) + 2*a(n-6) - 2*a(n-7).
Empirical g.f.: x*(2 + 2*x + 4*x^2 - x^3 + 4*x^4 - 2*x^6) / (1 - 2*x - x^2 - 3*x^3 - 2*x^5 - 2*x^6 + 2*x^7). - Colin Barker, Mar 10 2018
EXAMPLE
Some solutions for n=3:
..1..1....0..0....0..1....0..0....1..0....0..0....0..0....0..1....0..0....0..0
..0..0....0..0....0..0....0..1....0..0....0..0....1..0....0..0....1..0....0..0
..0..0....1..1....1..0....1..1....0..0....1..0....0..0....0..0....1..1....0..0
CROSSREFS
Cf. A218765.
Sequence in context: A002529 A217526 A018027 * A295499 A059413 A377118
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 05 2012
STATUS
approved