A193001 Number of n X n symmetric 0..7 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..7 introduced in lower triangular row major order

0, 1, 1, 6, 35, 697, 19477, 1567298, 211653572, 80504100636

Offset

1,4

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for 8X8 containing a 7
..0..0..1..1..3..3..3..3....0..0..1..1..3..3..5..5....0..0..1..1..3..3..5..5
..0..0..1..1..3..3..3..3....0..0..1..1..3..3..5..5....0..0..1..1..3..3..5..5
..1..1..2..2..1..1..5..5....1..1..2..2..4..4..6..6....1..1..2..2..2..2..6..6
..1..1..2..2..1..1..5..5....1..1..2..2..4..4..6..6....1..1..2..2..2..2..6..6
..3..3..1..1..4..4..6..6....3..3..4..4..2..2..7..7....3..3..2..2..4..4..7..7
..3..3..1..1..4..4..6..6....3..3..4..4..2..2..7..7....3..3..2..2..4..4..7..7
..3..3..5..5..6..6..7..7....5..5..6..6..7..7..6..6....5..5..6..6..7..7..2..2
..3..3..5..5..6..6..7..7....5..5..6..6..7..7..6..6....5..5..6..6..7..7..2..2

Crossrefs

Sequence in context: A192998 A192999 A193000 * A128298 A059059 A304255

Adjacent sequences: A192998 A192999 A193000 * A193002 A193003 A193004

Keyword

nonn

Author

R. H. Hardin Jul 14 2011

Status

approved