A269779 Number of length-7 0..n arrays with every repeated value unequal to the previous repeated value plus one mod n+1.

66, 1740, 14724, 73680, 270150, 804636, 2063880, 4728384, 9915210, 19361100, 35650956, 62496720, 105071694, 170405340, 267843600, 409579776, 611261010, 892675404, 1278524820, 1799288400, 2492181846, 3402217500, 4583370264

Offset

1,1

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 + 25*n^4 + 11*n^3 + n^2.

Conjectures from _Colin Barker_, Jan 29 2019: (Start)

G.f.: 6*x*(11 + 202*x + 442*x^2 + 152*x^3 + 27*x^4 + 6*x^5) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

Example

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

Crossrefs

Row 7 of A269776.

Sequence in context: A197645 A270847 A140925 * A279446 A271797 A017782

Adjacent sequences: A269776 A269777 A269778 * A269780 A269781 A269782

Keyword

nonn

Author

_R. H. Hardin_, Mar 04 2016

Status

approved