A269774 Number of length-n 0..6 arrays with every repeated value unequal to the previous repeated value plus one mod 6+1.

7, 49, 343, 2394, 16674, 115920, 804636, 5577768, 38621016, 267152256, 1846396944, 12751839072, 88012679328, 607126689792, 4186073691072, 28850627143296, 198768754154880, 1369007582681088, 9426405790368000, 64890966854407680

Offset

1,1

Links

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

Formula

Empirical: a(n) = 12*a(n-1) - 30*a(n-2) - 36*a(n-3).

Empirical g.f.: 7*x*(1 - 5*x - 5*x^2) / ((1 - 6*x)*(1 - 6*x - 6*x^2)). - Colin Barker, Jan 29 2019

Example

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

Crossrefs

Column 6 of A269776.

Sequence in context: A269433 A269688 A269492 * A269654 A250359 A045584

Adjacent sequences: A269771 A269772 A269773 * A269775 A269776 A269777

Keyword

nonn

Author

R. H. Hardin, Mar 04 2016

Status

approved