A193782 Number of n X n symmetric 0..3 arrays with no element equal to the sum or difference mod 4 of any two of its horizontal and vertical neighbors

4, 17, 77, 1099, 33151, 2100065, 268468949, 68719995395, 35184382602599, 36028797316842905, 73786976306927999773, 302231454904310883795947, 2475880078570809183639151007, 40564819207303345898201553712849

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..31

Example

Some solutions for 4X4
..3..3..3..3....3..3..1..3....3..3..1..1....1..3..3..1....1..1..3..1
..3..1..1..3....3..3..1..1....3..3..3..3....3..3..1..1....1..1..3..3
..3..1..1..3....1..1..1..3....1..3..1..1....3..1..3..1....3..3..3..3
..3..3..3..1....3..1..3..3....1..3..1..1....1..1..1..3....1..3..3..3

Crossrefs

Sequence in context: A123952 A005494 A257072 * A361454 A364030 A053486

Adjacent sequences: A193779 A193780 A193781 * A193783 A193784 A193785

Keyword

nonn

Author

R. H. Hardin Aug 05 2011

Status

approved