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A194889 Number of lower triangles of an n X n 0..4 array with new values introduced in row major order 0..4 and no two horizontal or vertical neighbors of any element equal 0
1, 3, 33, 1620, 136080, 17962560, 3751608960, 1233597237120, 641473938397440, 526921921428975360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 4 of A194893

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

Some solutions for 4X4

..0........0........0........0........0........0........0........0

..1.2......0.1......1.2......1.1......0.1......1.2......0.1......1.1

..3.0.1....2.3.4....1.3.0....2.3.4....2.1.3....1.2.3....2.1.0....2.3.3

..4.0.3.2..2.0.1.1..0.4.2.1..2.0.1.1..2.0.4.4..4.0.1.4..2.3.0.1..2.0.4.2

CROSSREFS

Sequence in context: A113111 A118188 A342170 * A126675 A038694 A319750

Adjacent sequences:  A194886 A194887 A194888 * A194890 A194891 A194892

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 04 2011

STATUS

approved

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Last modified January 23 21:06 EST 2022. Contains 350515 sequences. (Running on oeis4.)