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A243725 Number of length n+2 0..6 arrays with no three unequal elements in a row and no three equal elements in a row and new values 0..6 introduced in 0..6 order. 1
3, 6, 12, 25, 53, 116, 259, 594, 1389, 3323, 8095, 20112, 50805, 130560, 340597, 901889, 2420157, 6577868, 18083951, 50250422, 140966749, 398896687, 1137446947, 3265711480, 9432563169, 27389067476, 79894802085, 233989828069, 687661244273 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) - 54*a(n-3) + 50*a(n-4) + 172*a(n-5) - 181*a(n-6) - 244*a(n-7) + 180*a(n-8) + 144*a(n-9).
Empirical g.f.: x*(3 - 12*x - 24*x^2 + 115*x^3 + 77*x^4 - 370*x^5 - 176*x^6 + 406*x^7 + 235*x^8) / ((1 - 2*x)*(1 + 2*x)*(1 - 3*x)*(1 - x - x^2)*(1 - x - 3*x^2)*(1 - x - 4*x^2)). - Colin Barker, Nov 03 2018
EXAMPLE
Some solutions for n=6:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....0....1....1....0....1....1....1....0....1....0....0
..1....0....0....1....1....1....1....0....1....0....1....0....1....1....1....1
..2....0....0....2....0....0....2....0....0....0....0....1....0....2....0....1
..1....2....1....1....1....1....1....2....0....2....0....1....0....2....1....0
..2....0....0....1....1....1....2....2....1....0....2....2....2....1....0....1
..1....2....1....2....0....2....1....0....1....2....0....1....2....2....1....1
..2....2....0....2....0....1....1....0....2....0....0....1....0....1....0....2
CROSSREFS
Column 6 of A243729.
Sequence in context: A187260 A243723 A243724 * A243726 A243727 A243728
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 09 2014
STATUS
approved

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Last modified February 28 18:11 EST 2024. Contains 370400 sequences. (Running on oeis4.)