A194997 Number of lower triangles of an n X n 0..7 array with each element differing from all of its horizontal and vertical neighbors by one

8, 26, 138, 1104, 13754, 261324, 7686580, 346018484, 24069199390, 2566345975600, 422456182660436, 106689940668487188, 41576384767924321080, 24871115264481653525780, 22948996533081051784100632

Offset

1,1

Comments

Column 7 of A194998

Links

R. H. Hardin, Table of n, a(n) for n = 1..22

Example

Some solutions for 4X4
..2........6........2........2........2........0........2........2
..3.2......7.6......3.4......3.2......3.2......1.0......3.2......1.2
..2.1.0....6.5.6....2.3.2....2.1.0....2.3.2....2.1.0....2.3.2....2.3.2
..1.0.1.0..5.6.7.6..3.4.3.2..1.2.1.0..1.2.1.0..1.2.1.0..3.4.3.2..3.4.3.4

Crossrefs

Sequence in context: A260962 A274733 A223312 * A089064 A240291 A203635

Adjacent sequences: A194994 A194995 A194996 * A194998 A194999 A195000

Keyword

nonn

Author

R. H. Hardin Sep 07 2011

Status

approved