login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A255628 Number of length n+6 0..2 arrays with at most two downsteps in every n consecutive neighbor pairs 1
2187, 6561, 19683, 51768, 114546, 225253, 405687, 685713, 1103630, 1707576, 2557098, 3724906, 5298831, 7384008, 10105306, 13610028, 18070905, 23689409, 30699411, 39371211, 50015968, 62990559, 78702897, 97617739, 120263016 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A255622

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = (1/40320)*n^8 + (1/480)*n^7 + (13/192)*n^6 + (67/12)*n^5 + (48663/640)*n^4 + (46699/480)*n^3 + (5325055/2016)*n^2 - (53947/8)*n + 3866 for n>4

EXAMPLE

Some solutions for n=4

..2....0....2....1....2....0....1....0....1....0....1....0....2....1....0....2

..1....2....1....2....1....1....2....0....2....0....2....2....2....1....0....1

..0....2....2....0....1....0....2....0....0....2....0....1....2....1....2....2

..1....2....0....1....1....0....0....1....1....0....0....1....2....1....1....1

..1....2....1....0....1....1....0....1....0....2....1....2....1....0....2....2

..2....0....0....2....1....1....1....0....1....1....2....0....0....1....1....0

..0....2....0....0....1....0....2....1....2....2....2....0....1....1....1....0

..0....1....2....1....0....2....2....0....2....1....0....0....1....1....0....0

..1....1....0....0....0....1....0....1....0....2....1....0....2....2....0....0

..2....1....2....1....1....1....0....1....1....2....2....1....0....1....2....0

CROSSREFS

Cf. A255622

Sequence in context: A046320 A232926 A255113 * A232287 A219134 A233160

Adjacent sequences:  A255625 A255626 A255627 * A255629 A255630 A255631

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 28 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 5 03:31 EST 2020. Contains 338943 sequences. (Running on oeis4.)