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A211887 Number of lower triangular n X n arrays of integers 0 upwards introduced in row major order, with each element unique in its row and column, and containing the value n(n+1)/2-4 0
0, 0, 22, 957, 23267, 285622, 2223733 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 3 of A211888

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

Some solutions for n=4

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

..1.2......1.2......1.0......1.2......1.2......1.2......1.2......1.2

..3.4.5....3.4.1....2.1.3....3.4.0....3.0.4....3.0.4....3.4.1....2.3.4

..2.5.1.6..5.1.6.2..4.3.5.6..5.6.7.4..2.3.5.6..4.3.5.6..5.1.6.7..5.6.0.7

CROSSREFS

Sequence in context: A322930 A200575 A102995 * A041927 A041924 A160139

Adjacent sequences:  A211884 A211885 A211886 * A211888 A211889 A211890

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 24 2012

STATUS

approved

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Last modified July 24 11:06 EDT 2021. Contains 346273 sequences. (Running on oeis4.)