A269498 Number of length-7 0..n arrays with no repeated value differing from the previous repeated value by one.

66, 1609, 13946, 71115, 263794, 791381, 2039274, 4686391, 9847970, 19258689, 35501146, 62284739, 104779986, 170013325, 267327434, 408912111, 610410754, 891607481, 1277199930, 1797662779, 2490207026, 3399840069, 4580531626

Offset

1,1

Comments

Row 7 of A269494.

Links

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

Formula

Empirical: a(n) = n^7 + 7*n^6 + 21*n^5 + 15*n^4 + 7*n^3 + 17*n^2 - n - 1.

Empirical: x*(66 +1081*x +2922*x^2 +903*x^3 -122*x^4 +207*x^5 -18*x^6 +x^7) / (x-1)^8 . - R. J. Mathar, Mar 03 2016

Example

Some solutions for n=4
..1. .1. .3. .3. .1. .0. .3. .2. .2. .2. .2. .2. .2. .4. .1. .2
..1. .4. .1. .0. .4. .1. .2. .4. .1. .1. .4. .2. .2. .2. .0. .4
..1. .3. .2. .2. .3. .4. .2. .4. .1. .2. .0. .0. .4. .3. .4. .4
..3. .4. .0. .2. .4. .0. .1. .3. .3. .2. .3. .0. .3. .2. .1. .1
..3. .0. .1. .3. .0. .4. .4. .1. .4. .0. .0. .2. .0. .2. .4. .0
..1. .1. .0. .1. .4. .0. .0. .0. .3. .1. .0. .2. .3. .3. .3. .3
..4. .4. .0. .3. .4. .3. .3. .4. .0. .4. .0. .1. .0. .4. .2. .4

Crossrefs

Cf. A269494.

Sequence in context: A251047 A279889 A241799 * A133318 A197645 A270847

Adjacent sequences: A269495 A269496 A269497 * A269499 A269500 A269501

Keyword

nonn

Author

R. H. Hardin, Feb 28 2016

Status

approved