A269535 Number of length-n 0..6 arrays with no repeated value differing from the previous repeated value by other than one.

7, 49, 336, 2280, 15324, 102202, 677200, 4462414, 29265308, 191134204, 1243794600, 8068058218, 52186113316, 336696234188, 2167362918200, 13922979926042, 89273834257404, 571453869667592, 3652311182519800, 23309932135990218

Offset

1,1

Links

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

Formula

Empirical: a(n) = 26*a(n-1) - 246*a(n-2) + 896*a(n-3) + 123*a(n-4) - 6658*a(n-5) + 796*a(n-6) + 22824*a(n-7) + 23326*a(n-8) + 6924*a(n-9).

Empirical g.f.: x*(7 - 133*x + 784*x^2 - 674*x^3 - 6065*x^4 + 4181*x^5 + 26114*x^6 + 24478*x^7 + 7026*x^8) / ((1 - 6*x)*(1 - 20*x + 126*x^2 - 140*x^3 - 963*x^4 + 880*x^5 + 4484*x^6 + 4080*x^7 + 1154*x^8)). - Colin Barker, Jan 23 2019

Example

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

Crossrefs

Column 6 of A269537.

Sequence in context: A126639 A268942 A269638 * A269676 A269407 A269604

Adjacent sequences: A269532 A269533 A269534 * A269536 A269537 A269538

Keyword

nonn

Author

R. H. Hardin, Feb 29 2016

Status

approved