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A188822 Number of n X 7 binary arrays without the pattern 0 1 diagonally or antidiagonally. 1
128, 1156, 3888, 8836, 15776, 24964, 36000, 49284, 64416, 81796, 101024, 122500, 145824, 171396, 198816, 228484, 260000, 293764, 329376, 367236, 406944, 448900, 492704, 538756, 586656, 636804, 688800, 743044, 799136, 857476, 917664, 980100 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 7 of A188824.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4) for n>7.
Conjectures from Colin Barker, Apr 30 2018: (Start)
G.f.: 4*x*(32 + 225*x + 394*x^2 + 329*x^3 + 72*x^4 + 8*x^5 - 36*x^6) / ((1 - x)^3*(1 + x)).
a(n) = 2*(578 - 1088*n + 512*n^2) for n>3 and even.
a(n) = 2*(528 - 1088*n + 512*n^2) for n>3 and odd.
(End)
EXAMPLE
Some solutions for 3 X 7:
..1..1..1..0..1..1..1....1..1..1..1..1..0..1....1..1..1..1..1..1..1
..1..1..0..0..0..0..1....1..1..0..1..0..1..0....1..0..1..0..0..1..0
..0..0..0..0..0..0..0....1..0..1..0..0..0..0....0..1..0..0..0..0..0
CROSSREFS
Cf. A188824.
Sequence in context: A221599 A134630 A133061 * A181211 A221071 A070055
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 11 2011
STATUS
approved

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Last modified April 19 11:31 EDT 2024. Contains 371792 sequences. (Running on oeis4.)