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A208640 Number of 5 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors. 1
16, 89, 284, 722, 1652, 3577, 7504, 15448, 31440, 63543, 127884, 256718, 514556, 1030421, 2062360, 4126468, 8254936, 16512147, 33026868, 66056634, 132116516, 264236657, 528477344, 1056959152, 2113923232, 4227851887, 8455709724 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 5 of A208637.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) - 14*a(n-2) + 16*a(n-3) - 9*a(n-4) + 2*a(n-5) for n>7.
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(16 - 7*x - 26*x^2 + 8*x^3 + 16*x^4 - 2*x^5 - 4*x^6) / ((1 - x)^4*(1 - 2*x)).
a(n) = -84 + 63*2^n - (191*n)/6 - 4*n^2 - n^3/6 for n>2.
(End)
EXAMPLE
Some solutions for n=4:
..0..0..0..1....0..1..1..0....0..0..1..0....0..0..0..0....0..0..1..0
..1..1..0..1....0..0..1..0....1..0..1..0....1..1..1..0....1..0..1..0
..0..1..0..0....1..0..1..1....1..0..1..0....0..0..1..1....0..1..0..1
..0..1..1..1....1..0..0..1....1..0..1..0....1..0..0..1....1..0..1..0
..1..0..0..0....0..1..0..1....1..0..1..0....1..1..0..1....0..1..0..1
CROSSREFS
Cf. A208637.
Sequence in context: A120045 A301794 A301967 * A301888 A302084 A229399
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 29 2012
STATUS
approved

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)