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A235876
Number of (n+1)X(n+1) 0..2 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2X2 subblock
0
21, 105, 453, 1833, 7221, 28185, 109893, 429513, 1684821, 6633465, 26204133, 103802793, 412120821, 1639113945
OFFSET
1,1
COMMENTS
Diagonal of A235884
FORMULA
Empirical: a(n) = 10*a(n-1) -35*a(n-2) +50*a(n-3) -24*a(n-4)
EXAMPLE
Some solutions for n=5
..2..1..1..2..2..2....0..0..0..0..0..1....2..2..2..2..0..2....1..0..0..0..1..1
..1..2..2..1..1..1....0..0..0..0..0..1....2..2..2..2..0..2....0..1..1..1..0..0
..2..1..1..2..2..2....0..0..0..0..0..1....0..0..0..0..2..0....0..1..1..1..0..0
..2..1..1..2..2..2....0..0..0..0..0..1....2..2..2..2..0..2....0..1..1..1..0..0
..1..2..2..1..1..1....0..0..0..0..0..1....2..2..2..2..0..2....0..1..1..1..0..0
..2..1..1..2..2..2....0..0..0..0..0..1....0..0..0..0..2..0....0..1..1..1..0..0
CROSSREFS
Sequence in context: A126229 A060537 A116689 * A279763 A068986 A219631
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 16 2014
STATUS
approved