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.

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

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences: A233979 A233980 A233981 * A233983 A233984 A233985

Keyword

nonn

Author

R. H. Hardin, Dec 18 2013

Status

approved