login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A267236 Number of length-7 0..n arrays with no following elements greater than or equal to the first repeated value. 1

%I #8 Jan 10 2019 15:22:31

%S 9,479,5646,34396,143695,469623,1291052,3121008,6830757,13811655,

%T 26179802,47028540,80733835,133317583,212873880,330063296,498680193,

%U 736298127,1064998374,1512186620,2111502855,2903829511,3938402884

%N Number of length-7 0..n arrays with no following elements greater than or equal to the first repeated value.

%H R. H. Hardin, <a href="/A267236/b267236.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = n^7 + (69/20)*n^6 + (7/2)*n^5 + (7/6)*n^4 - (7/60)*n^2.

%F Conjectures from _Colin Barker_, Jan 10 2019: (Start)

%F G.f.: x*(9 + 407*x + 2066*x^2 + 2136*x^3 + 421*x^4 + x^5) / (1 - x)^8.

%F 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.

%F (End)

%e Some solutions for n=5:

%e ..3....0....1....1....0....1....0....4....1....5....1....0....1....4....1....3

%e ..1....3....5....3....5....2....4....3....0....3....5....2....5....1....0....0

%e ..0....0....3....4....0....5....3....2....5....5....5....5....5....0....2....4

%e ..1....4....0....1....2....3....2....5....1....3....1....3....4....3....0....5

%e ..4....5....1....3....1....0....4....5....3....1....1....1....4....1....3....5

%e ..5....3....2....4....0....1....3....2....4....3....3....0....2....4....2....2

%e ..2....2....2....3....5....2....1....2....4....1....3....2....0....0....4....3

%Y Row 7 of A267232.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 12 2016

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 2 12:49 EDT 2024. Contains 372196 sequences. (Running on oeis4.)