A195274 Number of lower triangles of an n X n integer array with each element differing from all of its vertical and horizontal neighbors by 4 or less and triangles differing by a constant counted only once

1, 81, 39609, 119743353, 2266745635377, 270149651796118149, 203368493873412168605037, 969036564714736790447759054277

Offset

1,2

Comments

Column 4 of A195278

Links

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

Example

Some solutions for n=5
...0...............0...............0...............0...............0
...1..4............1..1............1..0............2..5...........-3.-1
..-1..3..2.........4..3..7.........3..0..4.........1..2..6........-6.-5.-9
..-4.-1..3..7......3..6.10..7......1..2..0.-3......0..0..2..4.....-6.-7.-8-10
...0.-3..0..4..2...4..4..8..9..6...0..3..2..1..4..-4.-4.-1..2..2.-10-10.-8-11-13

Crossrefs

Sequence in context: A017200 A017308 A017428 * A189149 A088188 A017560

Adjacent sequences: A195271 A195272 A195273 * A195275 A195276 A195277

Keyword

nonn

Author

R. H. Hardin Sep 14 2011

Status

approved