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!)
A224556 Number of (n+2) X 7 0..1 matrices with each 3 X 3 subblock idempotent. 1
263, 246, 320, 395, 540, 740, 988, 1351, 1881, 2623, 3689, 5243, 7494, 10763, 15535, 22504, 32685, 47578, 69377, 101291, 148029, 216494, 316798, 463762, 679110, 994678, 1457123, 2134826, 3128004, 4583531, 6716662, 9842869, 14424498 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 5 of A224559.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 5*a(n-3) - 4*a(n-4) + 3*a(n-5) - a(n-6) for n>8.
Empirical g.f.: x*(263 - 806*x + 914*x^2 - 724*x^3 + 702*x^4 - 455*x^5 + 98*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Aug 31 2018
EXAMPLE
Some solutions for n=3:
..1..1..1..0..0..0..0....1..1..0..0..0..0..1....1..0..0..0..0..0..0
..0..0..0..0..0..0..0....0..0..0..0..0..0..1....1..0..0..0..0..0..0
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....1..0..0..0..0..0..0
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....0..0..0..0..0..0..0
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....1..0..0..0..1..1..1
CROSSREFS
Cf. A224559.
Sequence in context: A264972 A241877 A270752 * A052033 A105008 A345577
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 10 2013
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 July 15 12:21 EDT 2024. Contains 374332 sequences. (Running on oeis4.)