A269412 Number of length-6 0..n arrays with no repeated value greater than or equal to the previous repeated value.

16, 394, 2872, 12380, 39560, 104006, 238224, 492312, 939360, 1681570, 2857096, 4647604, 7286552, 11068190, 16357280, 23599536, 33332784, 46198842, 62956120, 84492940, 111841576, 146193014, 188912432, 241555400, 305884800, 383888466

Offset

1,1

Links

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

Formula

Empirical: a(n) = n^6 + 6*n^5 + 8*n^4 + (5/3)*n^3 - n^2 + (1/3)*n.

Conjectures from Colin Barker, Jan 21 2019: (Start)

G.f.: 2*x*(8 + 141*x + 225*x^2 - 5*x^3 - 9*x^4) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

Example

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

Crossrefs

Row 6 of A269409.

Sequence in context: A051360 A227390 A284854 * A269643 A071133 A186854

Adjacent sequences: A269409 A269410 A269411 * A269413 A269414 A269415

Keyword

nonn

Author

R. H. Hardin, Feb 25 2016

Status

approved