A195949 Number of lower triangles of an n X n 0..2 array with no element greater than the number its nonzero horizontal and vertical neighbors

1, 5, 124, 6466, 957659, 428469016, 558025290154, 2097314749929117, 22849041981438170008, 722512237126060035461636, 66280377620551351708766528619, 17635939684350970528621277455749104

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..19

Example

Some solutions for n=4
..0........0........1........0........0........1........1........1
..1.0......1.0......1.1......1.1......1.1......2.1......1.2......1.1
..1.1.1....1.0.1....1.2.0....2.1.1....1.2.0....2.1.1....1.2.0....1.1.0
..0.1.0.0..2.2.2.1..1.2.1.0..1.2.2.0..0.2.1.1..2.2.1.1..1.2.1.0..2.2.0.0

Crossrefs

Sequence in context: A196425 A362725 A193612 * A354654 A067081 A195801

Adjacent sequences: A195946 A195947 A195948 * A195950 A195951 A195952

Keyword

nonn

Author

R. H. Hardin Sep 25 2011

Status

approved