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A204860
Number of (n+2) X 3 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly two different ways, and new values 0..1 introduced in row major order
1
102, 382, 1437, 5352, 20113, 75595, 283877, 1066520, 4007148, 15055157, 56564804, 212519195, 798454799, 2999883555, 11270857666, 42345767978, 159097399097, 597745236156, 2245790151901, 8437664012699, 31701168874413, 119104542808892
OFFSET
1,1
COMMENTS
Column 1 of A204867.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +7*a(n-2) -8*a(n-4) +22*a(n-6) +41*a(n-7) +22*a(n-8) +13*a(n-9) -270*a(n-10) +64*a(n-11) +392*a(n-12) -424*a(n-13) +24*a(n-14) -228*a(n-15) +304*a(n-16) +200*a(n-17) -192*a(n-18) +32*a(n-19).
EXAMPLE
Some solutions for n=3
..0..0..0....0..1..1....0..0..0....0..1..1....0..0..1....0..1..1....0..0..0
..1..0..0....1..0..0....1..1..1....0..1..1....0..1..1....1..1..0....1..0..1
..0..1..1....0..0..0....1..1..0....1..0..1....0..1..1....1..1..0....1..1..0
..1..1..1....0..1..1....0..0..0....0..0..0....0..0..1....1..0..0....1..1..0
..0..1..0....0..0..1....0..1..1....0..0..1....0..0..1....0..1..0....0..1..1
CROSSREFS
Sequence in context: A140062 A203407 A204867 * A277459 A127655 A206659
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 20 2012
STATUS
approved