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A205257 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, and new values 0..1 introduced in row major order. 1
240, 1814, 13728, 103876, 785920, 5946280, 44989988, 340397184, 2575465940, 19486134776, 147433307220, 1115489560600, 8439863289268, 63856529812904, 483142470500100, 3655485938158424, 27657633637846868, 209259373825754344 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 1 of A205264.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) +7*a(n-2) +32*a(n-3) +34*a(n-4) +14*a(n-5) -20*a(n-6) -16*a(n-7).
Empirical g.f.: 2*x*(120 + 187*x + 582*x^2 + 565*x^3 + 180*x^4 - 352*x^5 - 256*x^6) / (1 - 6*x - 7*x^2 - 32*x^3 - 34*x^4 - 14*x^5 + 20*x^6 + 16*x^7). - Colin Barker, Jun 11 2018
EXAMPLE
Some solutions for n=3:
..0..1..1....0..0..1....0..1..0....0..1..1....0..1..1....0..0..0....0..0..1
..0..1..1....0..0..0....0..0..0....1..1..1....1..0..0....1..0..1....0..0..1
..0..0..0....1..1..1....0..1..1....1..1..1....1..0..0....1..1..0....0..1..1
..1..0..0....0..0..0....0..1..1....1..1..0....1..0..1....0..1..1....1..0..0
..0..1..1....0..1..0....0..0..1....1..0..1....1..0..1....0..1..1....1..0..0
CROSSREFS
Cf. A205264.
Sequence in context: A290655 A212781 A205264 * A049335 A004009 A269033
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 24 2012
STATUS
approved

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Last modified June 17 22:48 EDT 2024. Contains 373466 sequences. (Running on oeis4.)