A193501 Number of n X n symmetric 0..4 arrays with no element equal to the product mod 5 of any two of its horizontal and vertical neighbors

5, 71, 2558, 250860, 64996451, 45170582886, 83632270690739, 415014359673696258, 5503137668192072543375

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Example

Some solutions for 4X4
..1..0..2..2....1..3..1..0....0..1..0..1....2..0..3..1....0..1..3..2
..0..2..2..2....3..1..0..2....1..0..1..3....0..1..2..3....1..4..0..3
..2..2..3..3....1..0..1..0....0..1..0..4....3..2..3..1....3..0..2..2
..2..2..3..0....0..2..0..3....1..3..4..0....1..3..1..4....2..3..2..0

Crossrefs

Sequence in context: A349471 A347989 A193436 * A133990 A326881 A120808

Adjacent sequences: A193498 A193499 A193500 * A193502 A193503 A193504

Keyword

nonn

Author

R. H. Hardin Jul 29 2011

Status

approved