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A251146 Number of (n+1) X (5+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries. 1
213, 299, 433, 667, 1061, 1743, 2925, 5003, 8689, 15307, 27317, 49359, 90237, 166811, 311569, 587515, 1117445, 2141775, 4132941, 8022251, 15650353, 30663019, 60294293, 118919247, 235137501, 465904763, 924738385, 1838035483, 3657558629 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - 5*a(n-3) + a(n-4) + 2*a(n-5).
Empirical g.f.: x*(213 - 340*x - 464*x^2 + 433*x^3 + 342*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)). - Colin Barker, Nov 26 2018
EXAMPLE
Some solutions for n=4:
..1..1..1..2..0..1....1..2..1..2..0..1....2..1..2..1..1..1....1..0..1..0..2..1
..0..2..0..1..1..2....0..1..0..1..1..2....0..1..0..1..1..1....2..1..2..1..1..0
..1..1..1..2..0..1....2..1..2..1..1..0....1..2..1..2..0..2....1..0..1..0..2..1
..0..2..0..1..1..2....0..1..0..1..1..2....0..1..0..1..1..1....2..1..2..1..1..0
..1..1..1..2..0..1....2..1..2..1..1..0....1..2..1..2..0..2....0..1..0..1..1..2
CROSSREFS
Column 5 of A251149.
Sequence in context: A252032 A252025 A238019 * A085309 A252024 A302256
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 30 2014
STATUS
approved

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Last modified April 15 10:24 EDT 2024. Contains 371681 sequences. (Running on oeis4.)