A198482 - OEIS

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A198482

Number of 2n X 2 0..3 arrays with values 0..3 introduced in row major order and each element equal to an even number of horizontal and vertical neighbors.

5, 193, 10072, 528283, 27711478, 1453628917, 76251331828, 3999827976463, 209814352850962, 11005988987858473, 577328442763429648, 30284250801208664707, 1588585939401430092718, 83330616412779323165533 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	COMMENTS	`Column 1 of A198485.`
	LINKS	`R. H. Hardin, Table of n, a(n) for n = 1..200`
	FORMULA	`Empirical: a(n) = 55a(n-1) -135a(n-2) +81a(n-3) for n>4.` `Empirical g.f.: x(5 - 82x + 132x^2 - 27x^3) / ((1 - x)(1 - 54x + 81x^2)). - Colin Barker, May 14 2018`
	EXAMPLE	`Some solutions for n=3:` `..0..1....0..0....0..1....0..1....0..1....0..1....0..0....0..1....0..1....0..1` `..2..3....0..0....2..3....2..3....1..0....2..2....0..0....2..0....1..2....2..0` `..1..1....1..2....0..2....1..2....2..1....2..2....1..2....1..2....3..0....0..3` `..1..1....2..0....2..1....2..1....1..3....3..1....3..0....0..3....0..2....1..0` `..3..2....0..3....1..2....1..0....0..1....2..0....2..2....1..0....1..3....0..1` `..2..0....2..0....3..0....2..1....1..0....3..1....2..2....2..3....3..0....1..3`
	CROSSREFS	`Cf. A198485.` `Sequence in context: A100760 A240702 A240639 * A198523 A093154 A194572` `Adjacent sequences: A198479 A198480 A198481 * A198483 A198484 A198485`
	KEYWORD	`nonn`
	AUTHOR	`R. H. Hardin, Oct 25 2011`
	STATUS	`approved`

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Last modified August 15 13:59 EDT 2022. Contains 356145 sequences. (Running on oeis4.)