A242237 Number of length n+6+1 0..6 arrays with every value 0..6 appearing at least once in every consecutive 6+2 elements, and new values 0..6 introduced in order.

28, 70, 148, 298, 592, 1174, 2332, 4642, 9256, 18442, 36736, 73174, 145756, 290338, 578344, 1152046, 2294836, 4571230, 9105724, 18138274, 36130792, 71971246, 143364148, 285576250, 568857664, 1133144098, 2257182472, 4496226670

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..117

Formula

Empirical: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7).

Empirical g.f.: 2*x*(14 + 21*x + 25*x^2 + 26*x^3 + 24*x^4 + 19*x^5 + 11*x^6) / (1 - x - x^2 - x^3 - x^4 - x^5 - x^6 - x^7). - Colin Barker, Nov 01 2018

Example

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

Crossrefs

Column 6 of A242239.

Sequence in context: A039460 A245990 A110829 * A182465 A308703 A277987

Adjacent sequences: A242234 A242235 A242236 * A242238 A242239 A242240

Keyword

nonn

Author

R. H. Hardin, May 08 2014

Status

approved