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A204485
Number of (n+2) X 3 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly one way, and new values 0..1 introduced in row major order.
1
72, 214, 610, 1690, 4664, 12809, 35172, 96615, 265372, 728983, 2002395, 5500247, 15108294, 41499921, 113994101, 313124795, 860106901, 2362586936, 6489676798, 17826180446, 48965883404, 134502048011, 369457236654, 1014844430800
OFFSET
1,1
COMMENTS
Column 1 of A204492.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) -a(n-2) +4*a(n-3) -10*a(n-4) +18*a(n-6) -23*a(n-7) -3*a(n-9) +43*a(n-10) -86*a(n-11) +114*a(n-12) -85*a(n-13) +46*a(n-14) -16*a(n-15) -3*a(n-16) -4*a(n-17) +4*a(n-18) for n>19.
EXAMPLE
Some solutions for n=3
..0..0..0....0..1..0....0..0..1....0..0..1....0..1..1....0..0..1....0..1..0
..0..1..1....0..0..1....0..1..0....1..1..0....0..1..0....0..1..0....1..1..1
..1..0..0....1..1..1....0..1..1....0..0..0....1..1..0....1..1..1....0..0..1
..0..1..0....0..1..0....1..1..0....0..1..1....0..1..1....0..0..1....1..0..0
..0..1..0....1..0..0....0..1..1....1..1..0....1..1..0....0..1..0....0..0..1
CROSSREFS
Cf. A204492.
Sequence in context: A235186 A235179 A204492 * A358514 A344179 A050498
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 15 2012
STATUS
approved