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A208094
Number of n X 4 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal, diagonal or antidiagonal neighbor (colorings ignoring permutations of colors).
2
1, 5, 377, 169064, 235862938, 746823293346, 4493602584256529, 45881957995776221396, 734971289403287420883126, 17434398033181126785548889533, 585880828202059360820577364423099, 26929433656271781956071918468836389588, 1645382407173932261418519657416983542506695
OFFSET
0,2
LINKS
EXAMPLE
Some solutions for n=4
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..0..1..0..2....0..1..0..1....0..1..2..1....0..1..0..1....0..1..0..2
..2..1..0..1....2..1..0..2....0..1..0..1....0..2..0..1....2..1..0..1
..0..1..2..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..2
CROSSREFS
Column 4 of A208096.
Sequence in context: A072172 A278364 A214008 * A273397 A261433 A206386
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 23 2012
EXTENSIONS
a(0)=1 prepended and terms a(8) and beyond from Andrew Howroyd, May 17 2020
STATUS
approved