A269491 Number of length-n 0..5 arrays with no repeated value differing from the previous repeated value by one.

6, 36, 216, 1286, 7616, 44904, 263794, 1545030, 9026500, 52624694, 306261764, 1779708548, 10328981458, 59882754332, 346857774682, 2007544602552, 11611615811212, 67123684593712, 387837889353322, 2239991195959860

Offset

1,1

Links

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

Formula

Empirical: a(n) = 20*a(n-1) - 145*a(n-2) + 425*a(n-3) - 252*a(n-4) - 605*a(n-5) - 53*a(n-6) + 15*a(n-7).

Empirical g.f.: 2*x*(3 - 42*x + 183*x^2 - 182*x^3 - 286*x^4 - 22*x^5 + 7*x^6) / ((1 - 5*x)*(1 - 15*x + 70*x^2 - 75*x^3 - 123*x^4 - 10*x^5 + 3*x^6)). - Colin Barker, Jan 23 2019

Example

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

Crossrefs

Column 5 of A269494.

Sequence in context: A269580 A269432 A269687 * A269773 A269653 A250358

Adjacent sequences: A269488 A269489 A269490 * A269492 A269493 A269494

Keyword

nonn

Author

R. H. Hardin, Feb 28 2016

Status

approved