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A211925 Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal, vertical or antidiagonal neighbor, and containing the value n(n+1)/2-3 0
0, 2, 23, 340, 2577, 12616, 46582, 141478, 372360, 878257, 1899356, 3828287, 7278658, 13174305, 22863037, 38258971, 62017867, 97750188, 150276925, 225933542, 332927711, 481756822, 685691568 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A211930

LINKS

Table of n, a(n) for n=1..23.

FORMULA

Empirical: a(n) = (1/128)*n^8 + (1/32)*n^7 - (41/192)*n^6 - (1/4)*n^5 + (345/128)*n^4 - (367/96)*n^3 - (143/96)*n^2 + (169/24)*n - 3 for n>1

EXAMPLE

Some solutions for n=4

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

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

..3.1.4....3.4.5....3.4.2....3.4.5....2.3.4....3.4.5....3.1.4....3.4.2

..5.6.1.7..6.2.7.6..5.0.6.7..2.6.7.8..5.6.0.7..6.2.7.4..5.6.7.2..5.3.6.7

CROSSREFS

Sequence in context: A216549 A091693 A276025 * A277830 A197740 A234868

Adjacent sequences: A211922 A211923 A211924 * A211926 A211927 A211928

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 25 2012

STATUS

approved

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Last modified February 3 23:01 EST 2023. Contains 360045 sequences. (Running on oeis4.)