A268947 Number of length-6 0..n arrays with no repeated value unequal to the previous repeated value plus one mod n+1.

22, 396, 2780, 11950, 38322, 101192, 232696, 482490, 923150, 1656292, 2819412, 4593446, 7211050, 10965600, 16220912, 23421682, 33104646, 45910460, 62596300, 84049182, 111300002, 145538296, 188127720, 240622250, 304783102, 382596372

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 + 5*n^4 + 6*n^3 + 3*n^2 - n + 2.

Conjectures from Colin Barker, Jan 17 2019: (Start)

G.f.: 2*x*(11 + 121*x + 235*x^2 + 18*x^3 - 19*x^4 - 7*x^5 + x^6) / (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:
..6. .4. .5. .3. .1. .6. .2. .2. .0. .1. .1. .4. .5. .0. .6. .1
..4. .3. .2. .3. .6. .1. .6. .2. .2. .5. .3. .6. .6. .5. .2. .4
..5. .3. .4. .5. .5. .1. .6. .3. .2. .4. .0. .2. .2. .3. .6. .6
..3. .0. .3. .0. .0. .2. .0. .2. .0. .6. .0. .6. .5. .5. .3. .0
..1. .3. .4. .4. .5. .0. .2. .6. .1. .0. .2. .5. .1. .4. .6. .4
..5. .4. .3. .3. .5. .5. .5. .0. .5. .1. .6. .2. .4. .2. .5. .1

Crossrefs

Row 6 of A268944.

Sequence in context: A167033 A222886 A264464 * A159761 A049663 A246645

Adjacent sequences: A268944 A268945 A268946 * A268948 A268949 A268950

Keyword

nonn

Author

R. H. Hardin, Feb 16 2016

Status

approved