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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
1, 5, 124, 6466, 957659, 428469016, 558025290154, 2097314749929117, 22849041981438170008, 722512237126060035461636, 66280377620551351708766528619, 17635939684350970528621277455749104 (list; graph; refs; listen; history; text; internal format)
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: A320978 A196425 A193612 * A067081 A195801 A154022

Adjacent sequences:  A195946 A195947 A195948 * A195950 A195951 A195952

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 25 2011

STATUS

approved

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Last modified December 12 01:57 EST 2019. Contains 329948 sequences. (Running on oeis4.)