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A233982
Number of (n+1) X (1+1) 0..4 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 10, and no two adjacent values equal.
1
56, 236, 976, 4064, 16880, 70176, 291648, 1212224, 5038336, 20941056, 87037696, 361757184, 1503580160, 6249368576, 25974407168, 107958083584, 448708898816, 1864980094976, 7751463714816, 32217603784704, 133906837667840
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + 8*a(n-2) + 4*a(n-3).
Empirical g.f.: 4*x*(14 + 31*x + 14*x^2) / (1 - 2*x - 8*x^2 - 4*x^3). - Colin Barker, Oct 12 2018
EXAMPLE
Some solutions for n=5:
..1..0....1..0....2..3....1..3....2..3....2..3....2..1....3..1....4..2....1..3
..3..2....3..1....0..1....2..4....3..1....4..2....0..2....1..2....3..1....3..4
..1..3....1..2....2..0....3..2....4..3....3..4....2..1....3..4....2..0....1..3
..2..1....3..4....1..2....1..3....2..4....1..2....1..3....1..3....1..2....3..2
..0..2....1..2....3..4....2..4....1..3....3..4....3..2....2..1....3..1....2..4
..2..3....2..4....1..3....1..3....0..2....4..2....1..3....1..3....4..3....4..3
CROSSREFS
Column 1 of A233989.
Sequence in context: A193428 A179757 A233989 * A234769 A234762 A239597
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 18 2013
STATUS
approved