A193311 Number of n X n symmetric 0..5 arrays with no element equal to any horizontal or vertical neighbor, containing at least one 5 and with new values 0..5 introduced in lower triangular row major order

0, 0, 1, 4542, 14738163, 133285442691, 4508743067686948, 622715995190475951953, 359265265609409060043111601, 869862398667109067205080837833962

Offset

1,4

Links

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

Example

Some solutions for 4X4
..0..1..3..1....0..1..3..5....0..1..3..5....0..1..0..4....0..1..3..2
..1..2..4..2....1..2..4..3....1..2..0..2....1..2..3..0....1..2..4..5
..3..4..3..4....3..4..0..4....3..0..4..3....0..3..4..3....3..4..1..4
..1..2..4..5....5..3..4..1....5..2..3..1....4..0..3..5....2..5..4..1

Crossrefs

Sequence in context: A262848 A307919 A031607 * A020432 A186471 A210305

Adjacent sequences: A193308 A193309 A193310 * A193312 A193313 A193314

Keyword

nonn

Author

R. H. Hardin Jul 22 2011

Status

approved