A211929 Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal, vertical or antidiagonal neighbor, and containing the value n(n+1)/2-7

0, 0, 0, 6093, 8826873, 3020833719, 276214923832, 11092305676290

Offset

1,4

Comments

Column 6 of A211930

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
..1.2......1.2......1.0......1.2......1.2......1.2......1.2......1.2
..3.1.3....0.3.2....2.3.2....0.3.4....3.1.4....0.3.2....3.1.4....3.4.0
..2.4.2.0..4.1.4.1..4.1.5.2..5.2.0.3..5.2.5.1..1.4.5.0..5.2.3.2..5.1.4.3

Crossrefs

Sequence in context: A252329 A156200 A236824 * A251994 A201225 A031619

Adjacent sequences: A211926 A211927 A211928 * A211930 A211931 A211932

Keyword

nonn

Author

R. H. Hardin Apr 25 2012

Status

approved