A268942 Number of length-n 0..6 arrays with no repeated value unequal to the previous repeated value plus one mod 6+1.

7, 49, 336, 2275, 15239, 101192, 667065, 4370261, 28480312, 184750699, 1193659551, 7684815880, 49319275649, 315627565757, 2014797616440, 12831930191171, 81554529162967, 517343926505224, 3276087952780041, 20712766946115685

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 11*a(n-1) - 23*a(n-2) - 42*a(n-3).

Empirical g.f.: 7*x*(1 - 4*x - 6*x^2) / ((1 - 6*x)*(1 - 5*x - 7*x^2)). - Colin Barker, Jan 17 2019

Example

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

Crossrefs

Column 6 of A268944.

Sequence in context: A188868 A267469 A126639 * A269638 A269535 A269676

Adjacent sequences: A268939 A268940 A268941 * A268943 A268944 A268945

Keyword

nonn

Author

R. H. Hardin, Feb 16 2016

Status

approved