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A202790
Number of n X 3 binary arrays with every one adjacent to another one horizontally, diagonally, antidiagonally or vertically.
1
4, 50, 398, 3018, 23436, 182430, 1417772, 11017196, 85621362, 665418194, 5171353118, 40189602848, 312336995590, 2427354106352, 18864392868124, 146606264807250, 1139363300400646, 8854660691296250, 68814763405175276
OFFSET
1,1
COMMENTS
Column 3 of A202795.
LINKS
FORMULA
Empirical: a(n) = 7*a(n-1) +2*a(n-2) +29*a(n-3) +16*a(n-4).
Empirical g.f.: 2*x*(2 + 11*x + 20*x^2 + 8*x^3) / (1 - 7*x - 2*x^2 - 29*x^3 - 16*x^4). - Colin Barker, Jun 01 2018
EXAMPLE
Some solutions for n=5:
..1..0..1....1..0..0....1..0..0....1..1..0....1..1..0....1..1..1....0..1..0
..1..1..0....0..1..0....1..1..0....1..0..1....1..0..1....1..0..0....0..1..1
..0..1..0....1..1..0....1..1..1....1..1..0....1..1..0....1..1..1....1..1..0
..1..1..0....0..1..0....0..1..0....1..1..0....1..1..1....1..1..0....1..1..0
..0..0..1....0..1..0....1..0..0....0..1..0....1..0..0....0..1..0....0..1..1
CROSSREFS
Cf. A202795.
Sequence in context: A240396 A197473 A219566 * A231833 A028455 A232731
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 24 2011
STATUS
approved