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!)
A255109 Number of length n+2 0..2 arrays with at most one downstep in every n consecutive neighbor pairs. 1
27, 75, 168, 331, 597, 1008, 1616, 2484, 3687, 5313, 7464, 10257, 13825, 18318, 23904, 30770, 39123, 49191, 61224, 75495, 92301, 111964, 134832, 161280, 191711, 226557, 266280, 311373, 362361, 419802, 484288, 556446, 636939, 726467, 825768, 935619 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 2 of A255107.
LINKS
FORMULA
Empirical: a(n) = (1/120)*n^5 + (5/24)*n^4 + (37/24)*n^3 + (175/24)*n^2 + (239/20)*n + 6.
Empirical g.f.: x*(3 - 3*x + x^2)*(9 - 20*x + 18*x^2 - 6*x^3) / (1 - x)^6. - Colin Barker, Jan 24 2018
EXAMPLE
Some solutions for n=4:
0 2 2 0 2 2 1 0 0 1 1 1 1 2 2 2
0 2 0 1 0 2 1 0 2 1 0 1 1 1 0 2
0 1 2 0 1 2 1 0 0 2 0 2 0 1 1 0
1 1 2 1 2 0 0 2 0 1 0 2 0 1 1 0
0 1 2 2 2 2 1 2 0 1 2 1 1 1 2 0
1 1 2 2 2 2 2 2 1 2 1 2 1 2 2 1
CROSSREFS
Cf. A255107.
Sequence in context: A325824 A163506 A226357 * A369063 A297326 A044165
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2015
STATUS
approved

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 March 29 06:15 EDT 2024. Contains 371265 sequences. (Running on oeis4.)