A193783 Number of n X n symmetric 0..4 arrays with no element equal to the sum or difference mod 5 of any two of its horizontal and vertical neighbors

5, 32, 172, 2836, 91416, 5932132, 772063340, 201054032608, 104742810130844, 109165192335096960, 227605696416524730032, 949334416935490848158628, 7921224347549868400719029840, 132221576468713050783073932552152

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..16

Example

Some solutions for 4X4
..3..2..3..3....3..3..2..3....4..3..3..3....1..2..2..2....3..1..1..1
..2..2..2..2....3..3..2..2....3..3..2..2....2..2..2..3....1..1..4..1
..3..2..2..3....2..2..3..2....3..2..2..3....2..2..3..3....1..4..1..1
..3..2..3..3....3..2..2..2....3..2..3..2....2..3..3..4....1..1..1..3

Crossrefs

Sequence in context: A271455 A270423 A272448 * A271398 A006214 A157704

Adjacent sequences: A193780 A193781 A193782 * A193784 A193785 A193786

Keyword

nonn

Author

R. H. Hardin Aug 05 2011

Status

approved