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URL: https://oeis.org/A233402

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A233402
Number of (n+1) X (1+1) 0..2 arrays with row and column sums nondecreasing, and no adjacent elements equal.
1
9, 11, 22, 24, 41, 42, 66, 65, 97, 93, 134, 126, 177, 164, 226, 207, 281, 255, 342, 308, 409, 366, 482, 429, 561, 497, 646, 570, 737, 648, 834, 731, 937, 819, 1046, 912, 1161, 1010, 1282, 1113, 1409, 1221, 1542, 1334, 1681, 1452, 1826, 1575, 1977, 1703, 2134
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-2) - 3*a(n-4) + a(n-6).
Conjectures from Colin Barker, Oct 11 2018: (Start)
G.f.: x*(9 + 11*x - 5*x^2 - 9*x^3 + 2*x^4 + 3*x^5) / ((1 - x)^3*(1 + x)^3).
a(n) = (62 - 14*(-1)^n + (50-6*(-1)^n)*n + (11+(-1)^(1+n))*n^2) / 16.
(End)
EXAMPLE
Some solutions for n=5:
..2..0....0..1....0..1....1..0....0..1....0..2....0..1....1..0....1..0....0..1
..0..2....1..0....1..0....0..2....1..0....2..0....1..0....0..1....0..1....1..0
..2..0....0..2....0..2....2..0....0..1....0..2....0..2....1..0....2..0....2..1
..0..2....2..0....2..0....1..2....1..0....2..1....2..1....0..2....0..2....1..2
..2..1....0..2....0..2....2..1....2..1....1..2....1..2....2..1....2..1....2..1
..1..2....2..1....2..0....1..2....1..2....2..1....2..1....1..2....1..2....1..2
CROSSREFS
Column 1 of A233408.
Sequence in context: A022323 A106525 A103510 * A276406 A130730 A153697
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 09 2013
STATUS
approved