A208304 - OEIS

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A208304

Number of 4 X n nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).

1, 15, 877, 433252, 656404264, 2227156082842, 14216420563705724, 152834703739876070716, 2562708954761302163168116, 63338792205478132108785337770, 2209363673047740561377241754826088, 105080298194482216982100203776114994146, 6626004995903793205763315247117544349120572 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,2`
	LINKS	`Andrew Howroyd, Table of n, a(n) for n = 0..100`
	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..2..0....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..2` `..0..1..2..0....0..1..0..1....0..1..0..1....2..1..0..1....2..1..0..1` `..0..1..2..0....2..1..0..1....0..1..0..1....0..1..0..1....0..1..0..2`
	CROSSREFS	`Row 4 of A208301.` `Sequence in context: A223818 A208349 A121292 * A258796 A232364 A264562` `Adjacent sequences: A208301 A208302 A208303 * A208305 A208306 A208307`
	KEYWORD	`nonn`
	AUTHOR	`R. H. Hardin, Feb 25 2012`
	EXTENSIONS	`a(0)=1 prepended and terms a(8) and beyond from Andrew Howroyd, May 18 2020`
	STATUS	`approved`

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Last modified January 17 17:33 EST 2021. Contains 340247 sequences. (Running on oeis4.)