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A250661 Number of (7+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. 1
639, 1150, 1789, 2556, 3451, 4474, 5625, 6904, 8311, 9846, 11509, 13300, 15219, 17266, 19441, 21744, 24175, 26734, 29421, 32236, 35179, 38250, 41449, 44776, 48231, 51814, 55525, 59364, 63331, 67426, 71649, 76000, 80479, 85086, 89821, 94684, 99675 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 64*n^2 + 319*n + 256.
Conjectures from Colin Barker, Nov 16 2018: (Start)
G.f.: x*(639 - 767*x + 256*x^2) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)
EXAMPLE
Some solutions for n=4:
..1..1..1..1..1....1..1..0..0..0....1..1..0..0..0....0..0..0..0..0
..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..0..0..0..0..0....1..1..1..1..1....0..0..0..0..0....0..0..0..0..0
..1..1..1..1..1....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..1..1..1..1..1....0..0..0..0..0....0..0..0..0..0....1..1..1..1..1
..1..1..1..1..1....1..1..1..1..1....1..1..1..1..1....0..0..0..0..1
..0..0..0..0..0....1..1..1..1..1....0..0..0..0..0....0..0..0..0..1
..0..0..0..0..0....0..0..1..1..1....1..1..1..1..1....0..0..0..0..1
CROSSREFS
Row 7 of A250656.
Sequence in context: A360183 A281884 A200710 * A250587 A293922 A027885
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 26 2014
STATUS
approved

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Last modified June 20 23:53 EDT 2024. Contains 373535 sequences. (Running on oeis4.)