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A207993 Number of n X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors). 3
1, 3, 41, 1302, 96831, 16932816, 6978332618, 6787438272198, 15595829208171337, 84713253582265127190, 1088296274542436098185362, 33079232010276428576508643620, 2379573338713223879592059518246838 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Diagonal of A207997.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..16

EXAMPLE

Some solutions for n=4

..0..1..0..1....0..1..2..0....0..1..2..0....0..1..2..0....0..1..2..1

..1..2..1..0....1..0..1..2....2..0..1..2....1..2..0..2....2..0..1..2

..2..0..2..1....2..1..2..0....1..2..0..1....2..0..1..0....1..2..0..1

..0..1..0..2....0..2..0..1....2..1..2..0....1..2..0..1....2..0..1..0

MATHEMATICA

A207997 = Import["https://oeis.org/A207997/b207997.txt", "Table"][[All, 2]];

a[n_] := A207997[[2 n^2 - 2 n + 1]];

Table[a[n], {n, 1, 16}] (* Jean-Fran├žois Alcover, Sep 23 2019 *)

CROSSREFS

Sequence in context: A012129 A012035 A012016 * A187540 A012104 A012147

Adjacent sequences:  A207990 A207991 A207992 * A207994 A207995 A207996

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 22 2012

STATUS

approved

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Last modified July 31 02:33 EDT 2021. Contains 346367 sequences. (Running on oeis4.)