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A269471 Number of length-7 0..n arrays with no repeated value equal to the previous repeated value. 1
30, 1206, 11796, 63420, 242370, 741090, 1934856, 4488696, 9499590, 18678990, 34580700, 60879156, 102703146, 167030010, 263145360, 403173360, 602682606, 881372646, 1263846180, 1780471980, 2468343570, 3372338706, 4546284696 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = n^7 + 7*n^6 + 16*n^5 + 8*n^4 - n^3 - n.
Conjectures from Colin Barker, Jan 23 2019: (Start)
G.f.: 6*x*(5 + 161*x + 498*x^2 + 190*x^3 - 23*x^4 + 9*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:
..2. .0. .0. .0. .1. .1. .0. .0. .0. .1. .3. .0. .2. .3. .3. .0
..0. .2. .2. .3. .2. .3. .1. .2. .2. .2. .2. .1. .1. .3. .3. .1
..2. .2. .1. .0. .2. .1. .3. .2. .2. .2. .3. .0. .1. .1. .0. .3
..3. .0. .2. .3. .0. .2. .2. .0. .3. .3. .0. .2. .3. .0. .1. .0
..1. .1. .3. .2. .0. .3. .2. .0. .3. .2. .1. .2. .2. .2. .1. .0
..0. .1. .2. .0. .2. .3. .0. .1. .2. .3. .3. .3. .2. .1. .2. .3
..3. .2. .3. .1. .1. .2. .0. .0. .1. .1. .2. .1. .3. .3. .2. .3
CROSSREFS
Row 7 of A269467.
Sequence in context: A214820 A259462 A269682 * A060076 A174716 A163521
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 27 2016
STATUS
approved

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Last modified April 22 01:30 EDT 2024. Contains 371887 sequences. (Running on oeis4.)