A200249 Number of 0..5 arrays x(0..n-1) of n elements with each no smaller than the sum of its previous elements modulo 6.

6, 21, 75, 267, 951, 3387, 12063, 42963, 153015, 544971, 1940943, 6912771, 24620199, 87686139, 312298815, 1112268723, 3961403799, 14108748843, 50249054127, 178964660067, 637392088455, 2270105585499, 8085100933407, 28795513971219

Offset: 1

Author

R. H. Hardin, Nov 15 2011

Keywords

• nonn

Comments

Column 5 of A200251.

Examples

			Some solutions for n=6:
..2....2....3....2....0....0....3....3....2....3....3....3....1....0....1....3
..5....4....5....5....1....3....3....4....5....4....4....4....1....0....1....3
..2....3....5....1....5....5....2....5....4....5....2....3....2....5....2....0
..5....3....1....2....2....4....4....5....5....1....5....5....4....5....5....2
..5....2....5....5....3....4....5....5....4....3....5....4....2....5....4....4
..3....4....5....4....5....5....5....5....5....4....2....4....4....3....5....5
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..136

Crossrefs

Cf. A200251.

Formula

Empirical: a(n) = 3*a(n-1) +2*a(n-2).

Conjectures from Colin Barker, May 20 2018: (Start)

G.f.: 3*x*(2 + x) / (1 - 3*x - 2*x^2).

a(n) = (3*2^(-2-n)*((3-sqrt(17))^n*(-5+sqrt(17)) + (3+sqrt(17))^n*(5+sqrt(17)))) / sqrt(17).

(End)